Hardcodes the mapping for the SHA* hashes supported on WebAssembly from https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.cryptoconfig?view=net-5.0#remarks

Fixes https://github.com/dotnet/runtime/issues/44996

* Update dependencies from https://github.com/dotnet/runtime-assets build 20210420.1

System.ComponentModel.TypeConverter.TestData , System.Drawing.Common.TestData , System.IO.Compression.TestData , System.IO.Packaging.TestData , System.Net.TestData , System.Private.Runtime.UnicodeData , System.Runtime.TimeZoneData , System.Security.Cryptography.X509Certificates.TestData , System.Windows.Extensions.TestData
 From Version 6.0.0-beta.21219.1 -> To Version 6.0.0-beta.21220.1

* Update dependencies from https://github.com/dotnet/xharness build 20210422.3

Microsoft.DotNet.XHarness.CLI , Microsoft.DotNet.XHarness.TestRunners.Xunit
 From Version 1.0.0-prerelease.21220.1 -> To Version 1.0.0-prerelease.21222.3

* Update dependencies from https://github.com/dotnet/arcade build 20210421.1

Microsoft.DotNet.XUnitExtensions , Microsoft.DotNet.VersionTools.Tasks , Microsoft.DotNet.Build.Tasks.TargetFramework.Sdk , Microsoft.DotNet.Build.Tasks.Packaging , Microsoft.DotNet.Build.Tasks.Installers , Microsoft.DotNet.Build.Tasks.Feed , Microsoft.DotNet.CodeAnalysis , Microsoft.DotNet.Build.Tasks.Archives , Microsoft.DotNet.Arcade.Sdk , Microsoft.DotNet.ApiCompat , Microsoft.DotNet.XUnitConsoleRunner , Microsoft.DotNet.GenFacades , Microsoft.DotNet.GenAPI , Microsoft.DotNet.RemoteExecutor , Microsoft.DotNet.PackageValidation , Microsoft.DotNet.Helix.Sdk , Microsoft.DotNet.SharedFramework.Sdk
 From Version 6.0.0-beta.21219.2 -> To Version 6.0.0-beta.21221.1

* Update dependencies from https://github.com/dotnet/xharness build 20210423.1

Microsoft.DotNet.XHarness.CLI , Microsoft.DotNet.XHarness.TestRunners.Xunit
 From Version 1.0.0-prerelease.21220.1 -> To Version 1.0.0-prerelease.21223.1

* Revert downgrade of Microsoft.DotNet.Build.Tasks.Packaging
Co-authored-by: Ndotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>
Co-authored-by: NAlexander Köplinger <alex.koeplinger@outlook.com>

Convert a lot of function header comments to the current standard.
Write more documentation for many functions.
Remove a couple unused functions.

* Stop harvesting old frameworks in some libraries

The removed configurations (few netstandard1.x, portable*, netcore50)
of the touched packages aren't built anymore. Instead
the already built matching binaries from the latest available packages
are redistributed when packaging these libraries.

Dropping these assets as the minimum supported set of platforms are ones
that support netstandard2.0. For .NET Framework, there's still a net461
configuration present to avoid binding redirect issues.

Contributes to #47530

.. this will catch problems like https://github.com/dotnet/runtime/pull/51703
which caused rebuild errors:

```
   1>wasm-ld : error : duplicate symbol: mono_aot_module_System_Runtime_info [/Users/radical/dev/r3/src/mono/sample/wasm/console/Wasm.Console.Sample.csproj]
         >>> defined in /Users/radical/dev/r3/artifacts/obj/mono/Wasm.Console.Sample/wasm/Release/browser-wasm/wasm/System.Runtime.dll.bc
         >>> defined in /Users/radical/dev/r3/artifacts/obj/mono/Wasm.Console.Sample/wasm/Release/browser-wasm/wasm/System.Runtime.dll.bc
```

[main] Update dependencies from mono/linker

* IAsyncEnumerable deserializer should tolerate custom queue converters

* Update src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializer.Read.Stream.cs
Co-authored-by: NLayomi Akinrinade <layomia@gmail.com>

* address feedback

* update ILLink suppressions
Co-authored-by: NLayomi Akinrinade <layomia@gmail.com>

Mirror Android, the native APIs don't exist on iOS.

Contributes to #47910.

* To [JIT on Apple Silicon](https://developer.apple.com/documentation/apple-silicon/porting-just-in-time-compilers-to-apple-silicon) the application must call `pthread_jit_write_protect_np (0)` before writing to a code page and then `pthread_jit_write_protect_np (1)` before executing JITed code.

* Catalyst apps are Mac apps that get to use iOS frameworks (as well as some mac frameworks).  The API access is guarded by `__API_AVAILABLE` and `__API_UNAVAILABLE` macros in Apple framework headers.  If an API is not explicitly marked for catalyst, clang will follow the `ios` availability.

Unfortunately, `pthread_jit_write_protect_np` is marked like this:

```c
__API_AVAILABLE(macos(11.0))
__API_UNAVAILABLE(ios, tvos, watchos)
void pthread_jit_write_protect_np(int enabled);
```

So a Catalyst app running on arm64 cannot call it.  It will get a compile-time error.
```
src/mono/mono/utils/mono-codeman.c:669:3: error: 'pthread_jit_write_protect_np' is unavailable: not available on macCatalyst
                  pthread_jit_write_protect_np (0);
                  ^
  /Applications/Xcode_12.4.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk/usr/include/pthread.h:561:6: note: 'pthread_jit_write_protect_np' has been explicitly marked unavailable here
  void pthread_jit_write_protect_np(int enabled);
       ^
```

---

Turns out the symbol `pthread_jit_write_protect_np` is actually present in the Catalyst framework libraries, and it does the right thing.

This PR works around the unfortunate `pthread.h` declaration by not using it.

We create a new .c file that included our own declaration
```c
void pthread_jit_write_protect_np(int enabled);
```

And then a new `mono_jit_write_protect` function that calls the pthread function.

---

Another option would be to use something like
```
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wpartial-availability" 
...
#pragma clang diagnostic pop
```
around the offending callsites.  But neither ignoring `-Wpartial-availability` nor `-Wunguarded-availability-new` seem to have any effect on the compilation error.

---

Caveat: It's not yet clear whether this is ok to do in a retail (App Store) app.

---

* [mono] define HOST_MACCAT not HOST_MACCATALYST for Mac Catalyst

The C code already has HOST_MACCAT ifdefs.  HOST_MACCATALYST isn't used.

There are two sets of changes here:

- Make DacHeapWalker work for empty regions - I had observed a crash with the empty regions injected with STRESS_REGIONS.
- Make GetGCHeapStaticData robust against globals saved_sweep_ephemeral_seg and saved_sweep_ephemeral_start being null.

The changes should not cause issues for a coreclr NOT running with regions.

* Replace usage of NET50_OBSOLETIONS with NET5_0_OR_GREATER

* Correct GitHub handle

* Use a diagnostic id for the RuntimeEnvironment obsoletions from #50666

* Use fully-qualified attribute name in ref source updates from #49411

* Use a diagnostic id for the JsonSerializerOptions.IgnoreNullValues obsoletion from #41141

This functionality was removed as part of .NET Core, see https://github.com/dotnet/docs/issues/19944 for more info

* Update Font.cs

* Added test for GetHashCode pr #46816

* Added SkipOnTargetFramework as GetHashCode doesn't include font name in .NET Framework and changed FontFamily to SansSarif as per PR #47674. Fixes #44343. Original PR #46816.

* Update FontTests.cs

* Fix test, skip font if name is equal
Co-authored-by: NDan Moseley <danmose@microsoft.com>
Co-authored-by: NSantiago Fernandez Madero <safern@microsoft.com>

Co-authored-by: NDavid Wrighton <davidwr@microsoft.com>

* Fix symbolic link tests

Use IDisposable and `File.Delete` to ensure that symlinks get created
and cleaned up properly on all platforms. If all symlinks aren't
deleted, the later test cleanup phases have problems deleting them.

Fixes #51502

* Test still failing on Mac, skip until I can investigate

* WebRequest/ServicePoint/WebClient Obsoletion Follow-Up

* Suppress SYSLIB0014 at the project level for System.Net.Requests

* Improve documentation for obsoletion/analyzer diagnostics

* Clarity for SYSLIB0### and SYSLIB1### sequences

* Add info about the SYSLIB documentation pages

* Add pointer to the docs within Obsoletions.cs

- makes EAT build green again

* Add Pizza App for WASM SOD

* Fix missing paren

* Fix quoting

* Separate method for proxy scheme validation.

* Pass socks connection kind.

* Unauthorized socks5 connection.

* Username and password auth.

* Fix response address.

* Fix proxyUri value and assertion.

* Use HttpConnectionKind for SOCKS.

* Handle more connection kind assertions.

* SOCKS4/4a support.

* Move version selection into SocksHelper.

* Call sync version of read write.

* Cancellation by disposing stream.

* Dispose cancellation registration.

* IP addressing for SOCKS5.

* IP addressing for SOCKS4.

* Wrap write method.

* Cancellation and optimization.

* Optimize.

* Apply suggestions from code review
Co-authored-by: NMiha Zupan <mihazupan.zupan1@gmail.com>

* Clarify logic.

* Remove ssl assertion.

* SocksException.

* Make SocksException derive from IOException.

* Use binary primitives to write port in BE.

* Socks loopback test.

* Expand test matrix.

* Try to solve certificate issue.

* Pass handler to httpclient.

* Update ConnectToTcpHostAsync.

* Remove custom self-signed cert use from Socks test

* Fix LoopbackSocksServer's parsing of Socks4a domain name

* Only set RequestVersionExact for H2C

Setting it in general breaks H2 => H1.1 downgrade on platforms without ALPN

* Add auth test.

* Add IP in test matrix.

* Only override host when required.

* Don't attempt NT Auth for Socks proxies

* Skip HTTP2 ssl test on platforms without ALPN support

* Use NetworkCredential directly

* Pass AddressFamily to sync Dns resolution too

* Consistently check encoded string lengths

* Fix Socks5 user/pass auth

* Add IPv6 test for socks5

* Exception nits

* Add exceptional tests.

* Fix exceptional test.

* Fix NRT compilation
Co-authored-by: NMiha Zupan <mihazupan.zupan1@gmail.com>

* Server shouldn't wait for request in exceptional test.

* Add exception message to test.

* Update auth failure handling.

* SOCKS4 and 5 uses different auth model, requires different error message.

* Revert accidental indent change.

* Expand test matrix to include Sync HTTP1

* Read received bytes before returning error response in Socks4 loopback

* Use named bool arguments

* Improve exception messages

* !IsEmpty => Length != 0

* Improve exception messages 2

* Avoid enforing Socks4 VN value
Co-authored-by: NMiha Zupan <mihazupan.zupan1@gmail.com>

* remove repetitions ';'

* Cleanup XmlReader

* Cleanup XmlReaderAsync

* review feedback

* review feedback
Co-authored-by: Nkronic <kronic@softland.ru>

* Fix another hang on shutdown
- If SIGINT/Ctrl+C fires don't block shutdown waiting for dispose. This mechanism was intended to be a way to let application code unwind completely before exiting the process but we can cancel the the CancelKeyPress today, which means we don't need to wait for dispose to be called.
- This is a change in behavior but I can't figure out a case where ProcessExit would fire and you'd want it to wait on a dispose call *after* SIGINT/CTRL+C has fired.

* fix quic cert validation with OpenSSL

* feedback from review

* update certificate conditions

[main] Update dependencies from mono/linker

We didn't update the stack pointer after a return opcode.

The netstandard1.0 and portable* configurations of the
System.Composition.* packages aren't built anymore. Instead
the already built matching binary from the latest available package
version is redistributed when packaging these libraries.

Dropping the netstandard1.0 asset and the portable* one as the
minimum supported set of platforms are ones that support netstandard2.0.
For .NET Framework, there's still a net461 configuration to avoid
binding redirect issues.

Contributes to #47530