[llvm] Revert "[LoopVectorize] Add support for reverse loops in isDereferenceableAndAlignedInLoop (#96752)" (PR #123057)

[David Sherwood via llvm-commits]

david-arm wrote:

> It would be good to include a reason for the revert in the future in the commit message

Yep good point. I guess I was just panicking as I'd broken the build and wanted to get a fix up asap, but you're right in future I'll make sure to do that. 👍 

https://github.com/llvm/llvm-project/pull/123057