[runtime] Add %ToString and %_ToString and remove the TO_STRING builtin.

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 278 matching lines @@
 
 
 void JSGenericLowering::LowerJSToNumber(Node* node) {
   CallDescriptor::Flags flags = AdjustFrameStatesForCall(node);
   Callable callable = CodeFactory::ToNumber(isolate());
   ReplaceWithStubCall(node, callable, flags);
 }
 
 
 void JSGenericLowering::LowerJSToString(Node* node) {
-  ReplaceWithBuiltinCall(node, Context::TO_STRING_BUILTIN_INDEX, 1);
+  CallDescriptor::Flags flags = AdjustFrameStatesForCall(node);
+  Callable callable = CodeFactory::ToString(isolate());
+  ReplaceWithStubCall(node, callable, flags);
 }
 
 
 void JSGenericLowering::LowerJSToName(Node* node) {
   ReplaceWithRuntimeCall(node, Runtime::kToName);
 }
 
 
 void JSGenericLowering::LowerJSToObject(Node* node) {
   CallDescriptor::Flags flags = AdjustFrameStatesForCall(node);
@@ skipping 535 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSGenericLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8