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

[Chris Apple via cfe-commits]

cjappl wrote:

Pinging for a possible review:

@Sirraide @AaronBallman @MaskRay @vitalybuka @dougsonos 

Co-Author @davidtrevelyan 

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