[MLIR] NFC use Operation::getParentWithTrait in alloca verifier

[bondhugula]

Summary

Use recently added accessor Operation::getParentWithTrait in alloca
verifier.

[bondhugula]

Rebase

mlir/lib/Dialect/StandardOps/IR/Ops.cpp

static LogicalResult verify(AllocLikeOp op) {
   for (auto operandType : op.getOperandTypes())
     if (!operandType.isIndex())
       return op.emitOpError("requires operands to be of type Index");
 
   if (std::is_same<AllocLikeOp, AllocOp>::value)
     return success();
 
   // An alloca op needs to have an ancestor with an allocation scope trait.
-  auto *parentOp = op.getParentOp();
-  while (parentOp) {
-    if (parentOp->template hasTrait<OpTrait::AutomaticAllocationScope>())
-      return success();
-    parentOp = parentOp->getParentOp();
-  }
+  if (!op.template getParentWithTrait<OpTrait::AutomaticAllocationScope>())
     return op.emitOpError(
         "requires an ancestor op with AutomaticAllocationScope trait");
+
+  return success();
 }
 
 namespace {
 /// Fold constant dimensions into an alloc like operation.
 template <typename AllocLikeOp>
 struct SimplifyAllocConst : public OpRewritePattern<AllocLikeOp> {
   using OpRewritePattern<AllocLikeOp>::OpRewritePattern;