[clang] [MS ABI]: Support preserve_none in MS ABI (PR #96487)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman approved this pull request.

Generally LGTM, though the changes should come with a release note in `clang/docs/ReleaseNotes.rst` so users know about the fix.

https://github.com/llvm/llvm-project/pull/96487