Do not qualify member accesses that appear inside attributes.

Disable leak detection tests on x64

Merge dev15.9.x to master

Looks like RyuJIT change causes our leak detection tests to fail.
Disabling until we find a better pattern to use there.

https://github.com/dotnet/roslyn/issues/28639

Replace Nonshipping property with IsShipping

Update Language Feature Status

Add tests.

Merge dev15.8.x to dev15.9.x

Merge dev15.9.x to master

Merge dev15.8.x to dev15.9.x

Fix a bad merge

These two PRs were green but broke when built together:

- https://github.com/dotnet/roslyn/pull/28652
- https://github.com/dotnet/roslyn/pull/28420

When we enabled pointer_element_access to work on fixed sized buffers
regardless of the movability of the receiver of the buffer access, we
did not repair the safety rules to prevent leaking a pointer to a
moveable variable back into the language.

This change adds a new rule, which makes the movability of a
pointer_element_access on a fixed size buffer dependent on the
movability of its receiver. This should require the use of a `fixed`
statement to prevent safety holes.

Fixes #28476

Merge dev15.9.x to master

Fix tests to be only conditionally skipped

Clean up and align targets with RepoToolset