[llvm] [Transforms][Utils] Add LoopSplitUtils for iteration-space loop splitting (PR #205995)

[Ramkumar Ramachandra via llvm-commits]

================

----------------
artagnon wrote:

Wait, how can LatchCmp's parent not be the loop's latch?!

Why is the LatchCmp not part of isLegal? Should remove it from here?

https://github.com/llvm/llvm-project/pull/205995