Add fast paths for native RegExps in ES2015 subclass-aware code

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();
 
@@ skipping 13 matching lines @@
 // 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 !!REGEXP_UNICODE(this);
+  return TO_BOOLEAN(REGEXP_UNICODE(this));
 }
-%FunctionSetName(RegExpGetUnicode, "RegExp.prototype.unicode");
-%SetNativeFlag(RegExpGetUnicode);
+%SetForceInlineFlag(RegExpGetUnicode);
 
 utils.InstallGetter(GlobalRegExp.prototype, 'unicode', RegExpGetUnicode);
 
 })