[turbofan] Remove hack for dead nodes from JSGenericLowering.

src/compiler/js-generic-lowering.cc

 // Copyright 2014 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/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 178 matching lines @@
       op = machine()->IntLessThan();
       std::swap(true_value, false_value);
       break;
     default:
       UNREACHABLE();
   }
   Node* booleanize = graph()->NewNode(op, compare, jsgraph()->ZeroConstant());
 
   // Finally patch the original node to select a boolean.
   NodeProperties::ReplaceUses(node, node, compare, compare, compare);
-  // TODO(mstarzinger): Just a work-around because SelectLowering might
-  // otherwise introduce a Phi without any uses, making Scheduler unhappy.
-  if (node->UseCount() == 0) return;
   node->TrimInputCount(3);
   node->ReplaceInput(0, booleanize);
   node->ReplaceInput(1, true_value);
   node->ReplaceInput(2, false_value);
   node->set_op(common()->Select(kMachAnyTagged));
 }
 
 
 void JSGenericLowering::ReplaceWithStubCall(Node* node, Callable callable,
                                             CallDescriptor::Flags flags) {
@@ skipping 562 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSGenericLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8