[clang] [clang] Fix some static initialization race-conditions (PR #181367)

[Richard Dzenis via cfe-commits]

RIscRIpt wrote:

@dyung thanks. I am looking into this. I couldn't repro it on my mac, trying on Windows... I'll submit a follow up PR that fixes this problem once I manage to reproduce the problem.

https://github.com/llvm/llvm-project/pull/181367