[llvm] [LAA][NFC] Refactor deref no-wrap check; expose broken reverse-loop bounds (PR #211960)

[Aleksandr Popov via llvm-commits]

aleks-tmb wrote:

I believe all review comments have been addressed.

Since this is an NFC preparatory change needed for #211964, I’m going to land it. Further discussion of the functional change can continue in the follow-up. 

Thanks!

https://github.com/llvm/llvm-project/pull/211960