Correct and GC unrecognized flags from our tests.

tests/language/enum_syntax_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// SharedOptions=--enable-enum
-
 // Basic syntax test for enumeration types
 
 import 'package:expect/expect.dart';
 
 
 enum Color { red, orange, yellow, green }
 
 // Additional comma at end of list is ok.
 enum Veggies { carrot, bean, broccolo, }
 
@@ skipping 47 matching lines @@
   var x = zzTop.Frank;  /// 11: continued
 
   var x = new Rainbow();  /// 20: continued
   var x = new Rainbow();  /// 21: continued
   var x = new Rainbow();  /// 22: continued
 
   // It is a compile-time error to explicitly instantiate an enum instance.
   var x = new Color();  /// 30: compile-time error
 }