[llvm] [LLVM][rtsan] Add RealtimeSanitizer transform pass (PR #101232)

[Chris Apple via llvm-commits]

cjappl wrote:

Thanks for the reviews, now once the discussion on the attributes is finished in https://github.com/llvm/llvm-project/pull/100596 we can merge that, get green tests here and merge this.

I will ping this review again when that other one is completely settled. If anyone has any thoughts on the name of the attribute, please chime in over there.

https://github.com/llvm/llvm-project/pull/101232