[compiler-rt] [TSan] Add lock_during_write flag on Apple platforms to avoid deadlock (PR #157928)

[Mariusz Borsa via llvm-commits]

wrotki wrote:

Maybe the new flag should be documented in clang/docs/ThreadSanitizer.rst . The doc is sparse there (actually it doesn't mention any TSAN_OPTIONS). But AddressSanitizer.rst has some, with usage examples, so maybe we should follow the pattern.

https://github.com/llvm/llvm-project/pull/157928