[clang] [Clang] Add support for fp when using min_fetch/max_fetch atomics (PR #160330)

[Amina Chabane via cfe-commits]

Amichaxx wrote:

@CarolineConcatto Thanks for pointing that out, but I am a bit apprehensive to add Tim as he hasn't contributed to the project in nearly 2 years. Otherwise, I have added Sema tests in a separate file.

https://github.com/llvm/llvm-project/pull/160330