[llvm] [VPlan] Free removeDeadRecipes from VPPhi simplification (PR #156438)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> Is this NFC?

Very hard to prove that it is an NFC, so I've left it out of the title.

https://github.com/llvm/llvm-project/pull/156438