[llvm] StructurizeCFG: Optimize phi insertion during ssa reconstruction (PR #101301)

[via llvm-commits]

ruiling wrote:

> This PR seems to break HIP buildbot, causing Blender test to memfault:
> 
> https://lab.llvm.org/buildbot/#/builders/123/builds/3282

Thanks for the revert. @yxsamliu Is there any guide how to reproduce the Blender fail locally?

https://github.com/llvm/llvm-project/pull/101301