[llvm] [LV] Run VPlan licm late in executePlan (PR #181122)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

There is a non-trivial diff end-to-end on two benchmarks in MultiSource, presumably because LICMPass is only run late in the end-to-end pipeline, and running it earlier in VPlan permits simplification opportunities.

https://github.com/llvm/llvm-project/pull/181122