[llvm] [StructurizeCFG] nested-if zerocost hoist bugfix (PR #155408)

[Vigneshwar Jayakumar via llvm-commits]

VigneshwarJ wrote:

@shiltian , This PR is to fix multiple bugs that appeared in staging. Do you still want me to do CQE on it as it may take weeks?

https://github.com/llvm/llvm-project/pull/155408