[llvm] Revert gsymutil changes due to concurrency problems (PR #142829)

[Jacob Lalonde via llvm-commits]

Jlalond wrote:

@peremyach Let's add a bit more detail about ocassional crashes. Namely that we saw some SIGSEGV's that are likely due to concurrent access. Then we can land the revert :)

https://github.com/llvm/llvm-project/pull/142829