[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/builtins/builtins.h

 // Copyright 2011 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.
 
 #ifndef V8_BUILTINS_BUILTINS_H_
 #define V8_BUILTINS_BUILTINS_H_
 
 #include "src/base/flags.h"
 #include "src/handles.h"
 
@@ skipping 153 matching lines @@
   TFS(NonPrimitiveToPrimitive_Default, BUILTIN, kNoExtraICState,              \
       TypeConversion)                                                         \
   TFS(NonPrimitiveToPrimitive_Number, BUILTIN, kNoExtraICState,               \
       TypeConversion)                                                         \
   TFS(NonPrimitiveToPrimitive_String, BUILTIN, kNoExtraICState,               \
       TypeConversion)                                                         \
   TFS(StringToNumber, BUILTIN, kNoExtraICState, TypeConversion)               \
   TFS(ToName, BUILTIN, kNoExtraICState, TypeConversion)                       \
   TFS(NonNumberToNumber, BUILTIN, kNoExtraICState, TypeConversion)            \
   TFS(ToNumber, BUILTIN, kNoExtraICState, TypeConversion)                     \
+  TFS(ToString, BUILTIN, kNoExtraICState, TypeConversion)                     \
                                                                               \
   /* Handlers */                                                              \
   ASH(KeyedLoadIC_Megamorphic, KEYED_LOAD_IC, kNoExtraICState)                \
   TFS(KeyedLoadIC_Megamorphic_TF, KEYED_LOAD_IC, kNoExtraICState,             \
       LoadWithVector)                                                         \
   ASM(KeyedLoadIC_Miss)                                                       \
   ASH(KeyedLoadIC_Slow, HANDLER, Code::KEYED_LOAD_IC)                         \
   ASH(KeyedStoreIC_Megamorphic, KEYED_STORE_IC, kNoExtraICState)              \
   ASH(KeyedStoreIC_Megamorphic_Strict, KEYED_STORE_IC,                        \
       StoreICState::kStrictModeState)                                         \
@@ skipping 544 matching lines @@
 
   friend class Isolate;
 
   DISALLOW_COPY_AND_ASSIGN(Builtins);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_BUILTINS_BUILTINS_H_