[llvm] [MemProf] Fix when CallStackTrie is a single chain with multi alloc type (PR #79433)

[Teresa Johnson via llvm-commits]

teresajohnson wrote:

> > Interesting, I do agree that llvm-profdata should merge these. @snehasish is the person most familiar with the llvm-profdata code, but he is currently OOO as well.
> 
> @teresajohnson Thanks for reply. How about merging this PR to fix this corner case firstly? Or you want to modify llvm-profdata directly?

I think we should put in a fix for it now until it can be fixed in llvm-profdata. I had a suggestion on the PR.

https://github.com/llvm/llvm-project/pull/79433