Set max_atomic_width for AVR to 16

This is currently set to 0

https://github.com/rust-lang/rust/blob/90f0b24ad3e7fc0dc0e419c9da30d74629cd5736/compiler/rustc_target/src/spec/avr_gnu_base.rs#L26-L27

However, LLVM supports {8,16}-bit atomic load/store on AVR (support for RMW is still quite incomplete and only partially supported).

https://github.com/llvm/llvm-project/blob/llvmorg-15.0.0/llvm/test/CodeGen/AVR/atomics/load8.ll#L5-L13
https://github.com/llvm/llvm-project/blob/llvmorg-15.0.0/llvm/test/CodeGen/AVR/atomics/load16.ll#L3-L12
https://github.com/llvm/llvm-project/blob/llvmorg-15.0.0/llvm/test/CodeGen/AVR/atomics/store.ll#L3-L22

cc #99668

r? `@Amanieu`

Add trait decls to SMIR

r? `@oli-obk`

Closes https://github.com/rust-lang/project-stable-mir/issues/20

Bubble up nested goals from equation in `predicates_for_object_candidate`

This used to be needed for https://github.com/rust-lang/rust/pull/114036#discussion_r1273987510, but since it's no longer, I'm opening this as a separate PR. This also fixes one ICEing UI test: (`tests/ui/unboxed-closures/issue-53448.rs`)

r? `@lcnr`

Fix spurious test failure with `panic=abort`

Description on why it happens and why the fix should work is in the code comments.

⬆ `rust-analyzer`

r? `@ghost`

update Miri

Rollup of 8 pull requests

Successful merges:

 - #98935 (Implement `Option::take_if`)
 - #114093 (Add regression test for `echo 'mod unknown;' | rustc -`)
 - #114229 (Nest tests/codegen/sanitizer*.rs tests in sanitizer dir)
 - #114230 (Nest other codegen test topics)
 - #114362 (string.rs: remove "Basic usage" text)
 - #114365 (str.rs: remove "Basic usage" text)
 - #114382 (Add a new `compare_bytes` intrinsic instead of calling `memcmp` directly)
 - #114549 (Style fix and refactor on resolve diagnostics)

r? `@ghost`
`@rustbot` modify labels: rollup

Style fix and refactor on resolve diagnostics

- coding style
- refactor api of `span_look_ahead`

Add a new `compare_bytes` intrinsic instead of calling `memcmp` directly

As discussed in #113435, this lets the backends be the place that can have the "don't call the function if n == 0" logic, if it's needed for the target.  (I didn't actually *add* those checks, though, since as I understood it we didn't actually need them on known targets?)

Doing this also let me make it `const` (unstable), which I don't think `extern "C" fn memcmp` can be.

cc `@RalfJung` `@Amanieu`

str.rs: remove "Basic usage" text

Only one example is given

string.rs: remove "Basic usage" text

Only a single example is given

Nest other codegen test topics

This PR is like rust-lang/rust#114229 in that it mostly pushes codegen tests around, shoving them into their own directories, but because all of the changes are very simple cleanups I pulled them into a separate PR. The other PR might involve actually evaluating the correctness of the test after changes, but here it is mostly a matter of taste. The only "functional" change is deleting a few tests that... hinge on a version of LLVM that we don't support (as of rust-lang/rust#114148 anyways).

I considered a few different ways to group other topics but I feel the question of whether `tests/codegen/{vec,array,slice}` should exist is more subtle than these choices, as it might be better to group such related tests by other topics like bounds check elision, thus I avoided making it.

Nest tests/codegen/sanitizer*.rs tests in sanitizer dir

The sanitizer tests are the largest and most meticulously tested set of tests in tests/codegen. That's good! They all clearly belong to a subject and thus could go in a directory, but are not, instead being placed simply in tests/codegen. That's bad! Fix this by placing them in their own directory and renaming them to be less repetitive after that move.

A few tests are brittle, and embed their filename in the test's checks. This is acceptable for the ones where it is used only two times, but one test embeds the test's mangled filename in the test *over 50 times*! This may have been one of the things discouraging anyone from moving it, and thus from moving the set. Fortunately, I have some knowledge of Itanium mangling (involuntarily), regex, and the FileCheck syntax. With a capturing variable, FileCheck allows us to now move this test around again without diffing it on ~50 lines, while still guaranteeing that the mangled substring is the same each time.

This also clarifies why the substring is repeated a zillion times, instead of being cryptic. They don't call it mangling because the result is pretty and easy to understand, but now it is slightly easier! Yay descriptive variables!

Add regression test for `echo 'mod unknown;' | rustc -`

Closes #65601

The bug is fixed since long ago, probably by #69838 (see https://github.com/rust-lang/rust/issues/65601#issuecomment-1650508071 for more details).
Add a regression test so we can close the issue.

Implement `Option::take_if`

Tracking issue: #98934
ACP: rust-lang/libs-team#70 [accepted]

fix(ci): Ensure idempotence of user creation

Previously, re-running `run.sh` in the same container would fail at the useradd step, because the user already exists. Instead, change that step to "create if not exists" semantics to ease interactive debugging of CI failures.

Split out from https://github.com/rust-lang/rust/pull/111891 per request by `@jackh726`

Add more context to `quit_if_file_exists` in `configure.py` & delete config.toml in CI

If the `obj` directory isn't empty, the error message is subtle and not very helpful:

```
== clock drift check ==
  local time: Sun Jul  2 00:57:06 UTC 2023
  network time: Sun, 02 Jul 2023 00:57:06 GMT
== end clock drift check ==
sccache: Starting the server...
configure: error: Existing 'config.toml' detected.
== clock drift check ==
  local time: Sun Jul  2 00:57:06 UTC 2023
  network time: Sun, 02 Jul 2023 00:57:06 GMT
== end clock drift check ==
```

This makes it stand out and suggests how to resolve the issue:

```
== clock drift check ==
  local time: Sun Jul  2 02:11:30 UTC 2023
  network time: Sun, 02 Jul 2023 02:11:31 GMT
== end clock drift check ==
sccache: Starting the server...

configure: ERROR: Existing 'config.toml' detected. Exiting
Is objdir '/home/tmgross/projects/rust/obj' clean?

== clock drift check ==
  local time: Sun Jul  2 02:11:31 UTC 2023
  network time: Sun, 02 Jul 2023 02:11:31 GMT
== end clock drift check ==
```

Rollup of 6 pull requests

Successful merges:

 - #114535 (bump schannel, miow to drop windows-sys 0.42)
 - #114542 (interpret: use ConstPropNonsense for more const-prop induced issues)
 - #114543 (add tests for some fixed ConstProp ICEs)
 - #114550 (Generate better function argument names in global_allocator expansion)
 - #114556 (Issue numbers are enforced on active features; remove FIXME)
 - #114558 (Remove FIXME about NLL diagnostic that is already improved)

Failed merges:

 - #114485 (Add trait decls to SMIR)

r? `@ghost`
`@rustbot` modify labels: rollup

Co-authored-by: NRalf Jung <post@ralfj.de>

Remove FIXME about NLL diagnostic that is already improved

The FIXME was added in #46984 when the diagnostic message looked like this:

    // FIXME(#46983): error message should be better
    &s.0 //~ ERROR free region `` does not outlive free region `'static`

The message was improved in #90667 and now looks like this:

    &s.0 //~ ERROR lifetime may not live long enough

but the FIXME was not removed. The issue #46983 about that diagnostics should be improved has been closed. We can remove the FIXME now.

(This PR was made for #44366.)

Issue numbers are enforced on active features; remove FIXME

Since https://github.com/rust-lang/rust/pull/51090 tidy enforces that active features have an issue number, so remove the FIXME.

This PR is part of #44366 which is E-help-wanted.

Generate better function argument names in global_allocator expansion

Generated code for `#[global_allocator] static ALLOCATOR: Allocator = Allocator;`—

**Before:**

```rust
const _: () = {
    #[rustc_std_internal_symbol]
    unsafe fn __rust_alloc(arg0: usize, arg1: usize) -> *mut u8 {
        ::core::alloc::GlobalAlloc::alloc(
            &ALLOCATOR,
            ::core::alloc::Layout::from_size_align_unchecked(arg0, arg1),
        )
    }
    #[rustc_std_internal_symbol]
    unsafe fn __rust_dealloc(arg0: *mut u8, arg1: usize, arg2: usize) -> () {
        ::core::alloc::GlobalAlloc::dealloc(
            &ALLOCATOR,
            arg0,
            ::core::alloc::Layout::from_size_align_unchecked(arg1, arg2),
        )
    }
    #[rustc_std_internal_symbol]
    unsafe fn __rust_realloc(
        arg0: *mut u8,
        arg1: usize,
        arg2: usize,
        arg3: usize,
    ) -> *mut u8 {
        ::core::alloc::GlobalAlloc::realloc(
            &ALLOCATOR,
            arg0,
            ::core::alloc::Layout::from_size_align_unchecked(arg1, arg2),
            arg3,
        )
    }
    #[rustc_std_internal_symbol]
    unsafe fn __rust_alloc_zeroed(arg0: usize, arg1: usize) -> *mut u8 {
        ::core::alloc::GlobalAlloc::alloc_zeroed(
            &ALLOCATOR,
            ::core::alloc::Layout::from_size_align_unchecked(arg0, arg1),
        )
    }
};
```

**After:**

```rust
const _: () = {
    #[rustc_std_internal_symbol]
    unsafe fn __rust_alloc(size: usize, align: usize) -> *mut u8 {
        ::core::alloc::GlobalAlloc::alloc(
            &ALLOCATOR,
            ::core::alloc::Layout::from_size_align_unchecked(size, align),
        )
    }
    #[rustc_std_internal_symbol]
    unsafe fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize) -> () {
        ::core::alloc::GlobalAlloc::dealloc(
            &ALLOCATOR,
            ptr,
            ::core::alloc::Layout::from_size_align_unchecked(size, align),
        )
    }
    #[rustc_std_internal_symbol]
    unsafe fn __rust_realloc(
        ptr: *mut u8,
        size: usize,
        align: usize,
        new_size: usize,
    ) -> *mut u8 {
        ::core::alloc::GlobalAlloc::realloc(
            &ALLOCATOR,
            ptr,
            ::core::alloc::Layout::from_size_align_unchecked(size, align),
            new_size,
        )
    }
    #[rustc_std_internal_symbol]
    unsafe fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8 {
        ::core::alloc::GlobalAlloc::alloc_zeroed(
            &ALLOCATOR,
            ::core::alloc::Layout::from_size_align_unchecked(size, align),
        )
    }
};
```

add tests for some fixed ConstProp ICEs

Fixes https://github.com/rust-lang/rust/issues/96944
Fixes https://github.com/rust-lang/rust/issues/111353

interpret: use ConstPropNonsense for more const-prop induced issues

bump schannel, miow to drop windows-sys 0.42

Changes contains almost only of update to windows-sys 0.48
https://github.com/steffengy/schannel-rs/compare/v0.1.21...v0.1.22
https://github.com/yoshuawuyts/miow/compare/v0.5.0...v0.6.0

Steal MIR for CTFE when possible.

Some bodies, like constants, have CTFE MIR but no optimized MIR.
In that case, have `mir_for_ctfe` steal the MIR instead of cloning it.

Rollup of 5 pull requests

Successful merges:

 - #114466 (Add Allocation to SMIR)
 - #114505 (Add documentation to has_deref)
 - #114519 (use offset_of! to calculate dirent64 field offsets)
 - #114537 (Migrate GUI colors test to original CSS color format)
 - #114539 (linkchecker: Remove unneeded FIXME about intra-doc links)

Failed merges:

 - #114485 (Add trait decls to SMIR)

r? `@ghost`
`@rustbot` modify labels: rollup

The FIXME was added in 46984 when the diagnostic message looked like
this:

    // FIXME(#46983): error message should be better
    &s.0 //~ ERROR free region `` does not outlive free region `'static`

The message was improved in 90667 and now looks like this:

    &s.0 //~ ERROR lifetime may not live long enough

but the FIXME was not removed. The issue 46983 about that diagnostics
should be improved has been closed. We can remove the FIXME now.

Don't provide `generate_default_from_new` when impl self ty is missing

Also don't provide the assist when the `Default` trait can't be found.

Part of #15398

Also don't provide the assist when the `Default` trait can't be found.

parent_module_from_def_id does not need to be a query.

r? `@ghost`

linkchecker: Remove unneeded FIXME about intra-doc links

It was added by https://github.com/rust-lang/rust/pull/77971 but the adder [proposed](https://github.com/rust-lang/rust/pull/77971#issuecomment-710026798) that the added code is a good fallback to have in case rustdoc gets buggy, and I agree. So remove the FIXME.

This PR is part of #44366 which is E-help-wanted.

r? `@jyn514` since you added the FIXME

`@rustbot` label T-dev-tools