[llvm] [BOLT][NFC] Run ADRRelaxationPass in parallel (PR #67831)

[Vladislav Khmelevsky via llvm-commits]

yota9 wrote:

@rafaelauler To be honest I don't have big-enough binary right now to check. On a simple binary I see reduction from 3.3% user time to 0.  Anyway we have most of the passes run in parallel, I don't think it is a big deal to run this one too.. As for atomic I just don't see reason to use it here, since we only set variable to true and we don't really care about racing conditions in such situation...

https://github.com/llvm/llvm-project/pull/67831