[turbofan] Remove dead ChangeToUndefined in intrinsic lowering.

src/compiler/js-intrinsic-lowering.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-intrinsic-lowering.h"
 
 #include <stack>
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
@@ skipping 448 matching lines @@
   node->ReplaceInput(0, a);
   node->ReplaceInput(1, b);
   node->ReplaceInput(2, c);
   node->ReplaceInput(3, d);
   node->TrimInputCount(4);
   NodeProperties::ChangeOp(node, op);
   return Changed(node);
 }
 
 
-Reduction JSIntrinsicLowering::ChangeToUndefined(Node* node, Node* effect) {
-  ReplaceWithValue(node, jsgraph()->UndefinedConstant(), effect);
-  return Changed(node);
-}
-
-
 Reduction JSIntrinsicLowering::Change(Node* node, Callable const& callable,
                                       int stack_parameter_count) {
   CallDescriptor const* const desc = Linkage::GetStubCallDescriptor(
       isolate(), graph()->zone(), callable.descriptor(), stack_parameter_count,
       CallDescriptor::kNeedsFrameState, node->op()->properties());
   node->InsertInput(graph()->zone(), 0,
                     jsgraph()->HeapConstant(callable.code()));
   NodeProperties::ChangeOp(node, common()->Call(desc));
   return Changed(node);
 }
@@ skipping 19 matching lines @@
 }
 
 
 SimplifiedOperatorBuilder* JSIntrinsicLowering::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8