Revert "[MemProf] Add ambigous memprof attribute" (#161717)
Reverts llvm/llvm-project#157204
This caused issues in ThinLTO binaries because of the checking here,
that didn't expect allocations needing cloning to have memprof metadata:
https://github.com/llvm/llvm-project/blob/9133fc8cb04f8e45c9b46de85a8de99bf01e55c7/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp#L5572-L5582
I need to move the assert into the if check and guard by that condition.
And add a more thorough test.