[llvm] [LoopIdiom] Reland: Support 'shift until less-than' idiom #95002 (PR #98298)

[David Sherwood via llvm-commits]

https://github.com/david-arm commented:

Thanks for having another go at this @hazzlim! I just had one comment ...

https://github.com/llvm/llvm-project/pull/98298