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

src/x64/builtins-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1566 matching lines @@
   __ movp(rbx, rax);
   __ IncrementCounter(counters->string_ctor_string_value(), 1);
   __ jmp(&argument_is_string);
 
   // Invoke the conversion builtin and put the result into rbx.
   __ bind(&convert_argument);
   __ IncrementCounter(counters->string_ctor_conversions(), 1);
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
     __ Push(rdi);  // Preserve the function.
-    __ Push(rax);
-    __ InvokeBuiltin(Context::TO_STRING_BUILTIN_INDEX, CALL_FUNCTION);
+    ToStringStub stub(masm->isolate());
+    __ CallStub(&stub);
     __ Pop(rdi);
   }
   __ movp(rbx, rax);
   __ jmp(&argument_is_string);
 
   // Load the empty string into rbx, remove the receiver from the
   // stack, and jump back to the case where the argument is a string.
   __ bind(&no_arguments);
   __ LoadRoot(rbx, Heap::kempty_stringRootIndex);
   __ PopReturnAddressTo(rcx);
@@ skipping 258 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64