[llvm] [VPlan] Only use selectVectorizationFactor for cross-check (NFCI). (PR #103033)

[via llvm-commits]

================
@@ -9883,20 +9879,18 @@ bool LoopVectorizePass::processLoop(Loop *L) {
   unsigned UserIC = Hints.getInterleave();
 
   // Plan how to best vectorize, return the best VF and its cost.
----------------
ayalz wrote:

```suggestion
  // Plan how to best vectorize.
```

https://github.com/llvm/llvm-project/pull/103033