ES2015 web compat workaround: RegExp.prototype.flags => ""

test/mjsunit/regress/regress-crbug-581577.js

Index: test/mjsunit/regress/regress-crbug-581577.js
diff --git a/test/message/arrow-missing.js b/test/mjsunit/regress/regress-crbug-581577.js
similarity index 80%
copy from test/message/arrow-missing.js
copy to test/mjsunit/regress/regress-crbug-581577.js
index b9f9acd05c48ab3953d2a052efc3837b474fb88f..d95ada5f5a5719c1cfcc46b12c84c4f9974fb424 100644
--- a/test/message/arrow-missing.js
+++ b/test/mjsunit/regress/regress-crbug-581577.js
@@ -1,7 +1,5 @@
 // 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.
-//
-//
 
-function foo() { return(); }
+assertEquals("", RegExp.prototype.flags);