[llvm] [MemProf] Streamline and avoid unnecessary context id duplication (PR #107918)

[Snehasish Kumar via llvm-commits]

https://github.com/snehasish approved this pull request.

lgtm. 

nit: We should convert the callcontextinfo from a tuple to a struct at some point to make it easier to read the code here without having to refer to the decl. 

https://github.com/llvm/llvm-project/pull/107918