Correct and GC unrecognized flags from our tests.

tests/language/enum_duplicate_test.dart

 // Copyright (c) 2015, 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
-
 // Test for duplicate enums.
 
 library enum_duplicate_test;
 
 import 'package:expect/expect.dart';
 
 import 'enum_duplicate_lib.dart' as lib; /// 01: ok
 import 'enum_duplicate_lib.dart' as lib; /// 02: ok
 
 enum Enum1 {
   A,
   B,
 }
 
 enum Enum2 {
   A,
   B,
 }
 
 main() {
   Expect.equals('Enum1.A,Enum1.B', Enum1.values.join(','));
   Expect.equals('Enum1.A,Enum1.B', lib.Enum1.values.join(',')); /// 01: continued
   Expect.equals('Enum2.A,Enum2.B', Enum2.values.join(','));
   Expect.equals('Enum2.A,Enum2.B', lib.Enum2.values.join(',')); /// 02: continued
 }