[llvm] [LoopRotation] Enable LoopRotation with -Oz if header folds (PR #72842)

[via llvm-commits]

https://github.com/WenleiHe commented:

So if the heuristic determines we can rotate without duplication, the folding is guaranteed to happen right after rotate without anything interfering in between?  cc @kyulee-com who rely on Oz and is very sensitive to any size increase.

https://github.com/llvm/llvm-project/pull/72842