[llvm] [VPlan] Remove dead recipes before simplifying blends (PR #157622)

[Luke Lau via llvm-commits]

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

LGTM. And it looks like simplifyBlends calls recursivelyDeleteDeadRecipes after itself so we shouldn't need to run removeDeadRecipes after it.

https://github.com/llvm/llvm-project/pull/157622