[llvm] Reduce llvm-gsymutil memory usage (lambda-free, and less locking) (PR #97640)

[Kevin Frei via llvm-commits]

kevinfrei wrote:

> we centralized it in the ThreadSafeDWARFContext to avoid complicating other parts of libDebugInfoDWARF with thread safety concerns -> I wonder if this new concern can be factored into that existing design for the same reasons, so that thread safety concerns are relatively isolated/centralized

Got it! I stumbled across this stuff last night. It still triggers my threading anti-pattern eye-twitch, but the system is designed on top of that, so 🤷. I'll refactor/hoist the gsym usage out to use this interface instead.

https://github.com/llvm/llvm-project/pull/97640