[llvm] Fix non-determinism in debuginfo (PR #68332)

[Paul Kirth via llvm-commits]

ilovepi wrote:

I tried to think of a way to test this, but since its a non-determinism issue, the only way I was reliably able to trigger this was to LD_PRELOAD a different default allocator, which isn't something I think we can really do. If there is a good way to add a test for this, I'm happy to add one.

https://github.com/llvm/llvm-project/pull/68332