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

[Alexey Paznikov via llvm-commits]

apaznikov wrote:

Gentle ping. @dvyukov , @melver — I've updated this PR based on your suggestions:
1. The optimization is now enabled by default.
2. Added detailed documentation in the source code explaining the logic and safety guarantees.
3. Removed the experimental aggressive post-dom mode to ensure strict soundness.

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