Remove all harmony runtime flags which shipped in M51

src/js/harmony-unicode-regexps.js

-// 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.
-
-(function(global, utils) {
-
-'use strict';
-
-%CheckIsBootstrapping();
-
-// -------------------------------------------------------------------
-// Imports
-
-var GlobalRegExp = global.RegExp;
-var GlobalRegExpPrototype = GlobalRegExp.prototype;
-var MakeTypeError;
-
-utils.Import(function(from) {
-  MakeTypeError = from.MakeTypeError;
-});
-
-// -------------------------------------------------------------------
-
-// ES6 21.2.5.15.
-function RegExpGetUnicode() {
-  if (!IS_REGEXP(this)) {
-    // TODO(littledan): Remove this RegExp compat workaround
-    if (this === GlobalRegExpPrototype) {
-      %IncrementUseCounter(kRegExpPrototypeUnicodeGetter);
-      return UNDEFINED;
-    }
-    throw MakeTypeError(kRegExpNonRegExp, "RegExp.prototype.unicode");
-  }
-  return TO_BOOLEAN(REGEXP_UNICODE(this));
-}
-%SetForceInlineFlag(RegExpGetUnicode);
-
-utils.InstallGetter(GlobalRegExp.prototype, 'unicode', RegExpGetUnicode);
-
-})