[llvm] [VPlan] Fix header phi VPInstruction verification. NFC (PR #151472)

[Florian Hahn via llvm-commits]

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@@ -80,8 +80,8 @@ bool VPlanVerifier::verifyPhiRecipes(const VPBasicBlock *VPBB) {
       NumActiveLaneMaskPhiRecipes++;
 
     if (IsHeaderVPBB && !isa<VPHeaderPHIRecipe, VPWidenPHIRecipe>(*RecipeI) &&
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fhahn wrote:

```suggestion
    if (IsHeaderVPBB && !isa<VPHeaderPHIRecipe, VPWidenPHIRecipe, VPPhi>(*RecipeI) &&
```

This can just use VPPhi I think.

https://github.com/llvm/llvm-project/pull/151472