[llvm] [llvm-gsymutil] Address merged-funcs test non-determinism (PR #122308)

[via llvm-commits]

alx32 wrote:

@vvereschaka - Yes, the fix is this: https://github.com/llvm/llvm-project/pull/122921

I will merge soon as soon as I confirm the windows failiure is unrelated. 

https://github.com/llvm/llvm-project/pull/122308