[llvm] VPlan: increase simplification power of simplifyRecipe (PR #93998)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

Honestly, I'm not sure what value #105699 adds, but this patch should be good now, either to be merged after #105699, or subsuming #105699 altogether.

https://github.com/llvm/llvm-project/pull/93998