[clang] [clang][rtsan] Introduce realtime sanitizer codegen and driver (PR #102622)

[Chris Apple via cfe-commits]

cjappl wrote:

Out of an abundance of caution I have reverted this. I am still unsure of what in my code could have caused this failure.

 If anyone out there has a bright idea please let me know. I will monitor the builds for a bit and ensure they are back to green

https://github.com/llvm/llvm-project/pull/102622