[llvm] [LV][EVL] Fix the check for legality of folding with EVL. (PR #125678)

[Luke Lau via llvm-commits]

https://github.com/lukel97 approved this pull request.

LGTM, I think I remember seeing this problem when even after implementing widening IVs there were still loops not being vectorized when they were without EVL tail folding. Thanks for fixing this!

https://github.com/llvm/llvm-project/pull/125678