[clang] [Clang] Fix __{add, remove}_pointer in Objective-C++ (PR #123678)

[Aaron Ballman via cfe-commits]

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

Oof, I'd like to hear from @rjmccall -- Objective-C pointer types are not C pointer types.

https://github.com/llvm/llvm-project/pull/123678