[json] replace remaining json.js code with C++ builtins.

src/js/json.js

-// Copyright 2009 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.
-
-(function(global, utils) {
-
-"use strict";
-
-%CheckIsBootstrapping();
-
-// -------------------------------------------------------------------
-// Imports
-
-var GlobalDate = global.Date;
-var GlobalJSON = global.JSON;
-var GlobalSet = global.Set;
-var InternalArray = utils.InternalArray;
-var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
-
-// -------------------------------------------------------------------
-
-function JSONParse(text, reviver) {
-  return %ParseJson(text, reviver);
-}
-
-// -------------------------------------------------------------------
-
-%AddNamedProperty(GlobalJSON, toStringTagSymbol, "JSON", READ_ONLY | DONT_ENUM);
-
-// Set up non-enumerable properties of the JSON object.
-utils.InstallFunctions(GlobalJSON, DONT_ENUM, [
-  "parse", JSONParse,
-]);
-
-// -------------------------------------------------------------------
-// Date.toJSON
-
-// 20.3.4.37 Date.prototype.toJSON ( key )
-function DateToJSON(key) {
-  var o = TO_OBJECT(this);
-  var tv = TO_PRIMITIVE_NUMBER(o);
-  if (IS_NUMBER(tv) && !NUMBER_IS_FINITE(tv)) {
-    return null;
-  }
-  return o.toISOString();
-}
-
-// Set up non-enumerable functions of the Date prototype object.
-utils.InstallFunctions(GlobalDate.prototype, DONT_ENUM, [
-  "toJSON", DateToJSON
-]);
-
-})