[llvm] [MemorySSA] Relax clobbering checks for calls to consider writes only (PR #179721)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

@CarolineConcatto Nit: I took liberty of renaming the PR title. If possible, we usually prefer the name of the main subcomponent for changes in LLVM core. Among other things, it may help people identify the area / make it easier for triage at a glance.

https://github.com/llvm/llvm-project/pull/179721