[llvm] [TSan] Add dominance-based redundant instrumentation elimination (PR #169897)

[Dmitry Vyukov via llvm-commits]

https://github.com/dvyukov commented:

The high-level algorithm looks good to me.
I don't have time for very detailed review. Will leave to @vitalybuka and @melver 

https://github.com/llvm/llvm-project/pull/169897