[llvm] Revert "[StructurizeCFG] Hoist and simplify zero-cost incoming else phi values" (PR #148016)

[Shilei Tian via llvm-commits]

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

You don't need a PR to revert. Just revert it locally and push directly to `main`, but please include the reason for the revert in the commit description.

https://github.com/llvm/llvm-project/pull/148016