[clang] Sema: Fix CXXRecordDecl::isTriviallyCopyable() for classes with all deleted special functions. (PR #94831)

[Aaron Ballman via cfe-commits]

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

LGTM, though please add a release note to `clang/docs/ReleaseNotes.rst` so users know about the fix.

We should keep our eyes peeled for any ABI fallout from this change (changing the way type traits respond often leads to surprising ABI breaks) -- we may need to put in some ABI tag checking if there's fallout.

https://github.com/llvm/llvm-project/pull/94831