[clang] [Sema] Check arg count for builtins with CustomTypeChecking (PR #222841)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Please be sure to also add a release note to `clang/docs/ReleaseNotes.md` so users know about the fix.

https://github.com/llvm/llvm-project/pull/222841