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

[Luke Lau via llvm-commits]

================
@@ -195,6 +197,9 @@ bool VPlanVerifier::verifyVPBasicBlock(const VPBasicBlock *VPBB) {
       return false;
     }
     for (const VPValue *V : R.definedValues()) {
+      // Verify that recipes' operands have matching types.
+      TypeInfo.inferScalarType(V);
----------------
lukel97 wrote:

Good point. I'm trying to exercise the assertions in VTypeAnalysis, and I guess it was working because all the callers of `verifyVPlanIsValid` happen to already be asserts.

Maybe it would make more sense just to pull this out of VPlanVerifier and instead at the call sites add something like:

```c++
[[maybe_unused]] VTypeAnalysis TypeInfo(Plan->getCanonicalIV()->getScalarType());
assert(TypeInfo.inferScalarType(V));
```

i.e. use assert to invoke more asserts.

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