Add missing copyright on test cases.

pkg/front_end/testcases/redirecting_factory.dart

Index: pkg/front_end/testcases/redirecting_factory.dart
diff --git a/pkg/front_end/testcases/redirecting_factory.dart b/pkg/front_end/testcases/redirecting_factory.dart
index 9ee5b829d6f82c52bac782006f06cb54a2d24462..af4e16d86ec4588428ef1c50627f0ebf2a06dd10 100644
--- a/pkg/front_end/testcases/redirecting_factory.dart
+++ b/pkg/front_end/testcases/redirecting_factory.dart
@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 abstract class FooBase<Tf> {
   int get x;
   factory FooBase(int x) = Foo<Tf>;