[compiler-rt] [RTSan][Darwin] Adjust OSSpinLock/_os_nospin_lock interceptor and tests (PR #132867)

[via llvm-commits]

thetruestblue wrote:

> Thanks for circling back to this! What was the big difference maker in this version?
> 
> LGTM

Previously we were getting name duplication errors with our SDKs. This just makes the forward declaration match whats in the header.

https://github.com/llvm/llvm-project/pull/132867