[es6] implement RegExp.@@search.

test/mjsunit/es6/string-search.js

 // Copyright 2015 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.
 
 // Flags: --harmony-regexp-subclass
 
 var pattern = {};
-pattern[Symbol.match] = function(string) {
+pattern[Symbol.search] = function(string) {
   return string.length;
 };
 // Check object coercible fails.
-assertThrows(() => String.prototype.match.call(null, pattern),
+assertThrows(() => String.prototype.search.call(null, pattern),
              TypeError);
 // Override is called.
-assertEquals(5, "abcde".match(pattern));
+assertEquals(5, "abcde".search(pattern));
 // Non-callable override.
-pattern[Symbol.match] = "dumdidum";
-assertThrows(() => "abcde".match(pattern), TypeError);
+pattern[Symbol.search] = "dumdidum";
+assertThrows(() => "abcde".search(pattern), TypeError);
 
-assertEquals("[Symbol.match]", RegExp.prototype[Symbol.match].name);
+assertEquals("[Symbol.search]", RegExp.prototype[Symbol.search].name);