[llvm] [LoopSimplifyCFG] Fix SCEV invalidation after removing dead exit (PR #127536)

[Aleksandr Popov via llvm-commits]

aleks-tmb wrote:

> Could you please provide some more info on what happens in the test case? Like what the problematic SCEVs are that currently don't get invalidated.

Sure, I've added details to the issue: https://github.com/llvm/llvm-project/issues/127534

https://github.com/llvm/llvm-project/pull/127536