[llvm] [VPlan] Verify scalar types in VPlanVerifier. NFCI (PR #122679)

[Florian Hahn via llvm-commits]

================
@@ -195,6 +197,12 @@ bool VPlanVerifier::verifyVPBasicBlock(const VPBasicBlock *VPBB) {
       return false;
     }
     for (const VPValue *V : R.definedValues()) {
+      // Verify that recipes' operands have matching types.
----------------
fhahn wrote:

Might be more precise to say something like below. The code here just checks that the type is non-null, matching types are only check internally by inferScalarType.

```suggestion
      // Verify that we can infer a scalar type for each defined value. With assertions enabled, inferScalarType will perform some consistency checks during type inference.
```



https://github.com/llvm/llvm-project/pull/122679