[llvm] [LTO] Fix a crash with thin LTO caching and asm output (PR #138203)

[Teresa Johnson via llvm-commits]

https://github.com/teresajohnson requested changes to this pull request.

Looking at this again and at the commit function, I'm not really sure how they are related. Can you clarify (see questions below)?

https://github.com/llvm/llvm-project/pull/138203