[llvm] [LoopInterchange] Prevent from undoing its own transformation (PR #127473)

[Ryotaro Kasuga via llvm-commits]

https://github.com/kasuga-fj commented:

The description was really bad. This patch fixes the issue that LoopInterchange can undo its optimization, as I described in https://github.com/llvm/llvm-project/pull/118267#issuecomment-2510759354. I don't intend to archive the global optimal order. Fixed the PR title and description.

https://github.com/llvm/llvm-project/pull/127473