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

[Ashutosh Nema via llvm-commits]

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

----------------
nema-ashutosh wrote:

Generalizing to arbitrary constant strides is already planned and handled in the full patch(#209142). I intentionally left it out of the first patch to keep the change simple and the review scope focused. Support for it is planned as a follow-up in the next patch

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