[VPlan] Use TypeAnalysis instead of underlying instr in VPPredInst (NFC)

Removes another unnecessary use of the underlying instructions during
VPlan execution.

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -2642,7 +2642,7 @@ void VPPredInstPHIRecipe::execute(VPTransformState &State) {
     if (vputils::onlyFirstLaneUsed(this) && !State.Lane->isFirstLane())
       return;
 
-    Type *PredInstType = getOperand(0)->getUnderlyingValue()->getType();
+    Type *PredInstType = State.TypeAnalysis.inferScalarType(getOperand(0));
     PHINode *Phi = State.Builder.CreatePHI(PredInstType, 2);
     Phi->addIncoming(PoisonValue::get(ScalarPredInst->getType()),
                      PredicatingBB);