[clang] [Bounds-Safety] Add sized_by, counted_by_or_null & sized_by_or_null (PR #93231)

[Dan Liew via cfe-commits]

https://github.com/delcypher requested changes to this pull request.

I'm requesting changes for now but we can change this based on @rapidsna 's opinion.

https://github.com/llvm/llvm-project/pull/93231