[clang] Add check in SemaChecking for multiple unsequenced volatile accesses (PR #180955)

[Corentin Jabot via cfe-commits]

cor3ntin wrote:

This looks pretty neat


This change needs a release note.
Please add an entry to `clang/docs/ReleaseNotes.rst` in the section the most adapted to the change, and referencing any Github issue this change fixes. Thanks!!

https://github.com/llvm/llvm-project/pull/180955