Add missing copyright on test cases.

pkg/front_end/testcases/static_setter.dart

Index: pkg/front_end/testcases/static_setter.dart
diff --git a/pkg/front_end/testcases/static_setter.dart b/pkg/front_end/testcases/static_setter.dart
index a79627bf49feb76ffac51c5b0b6868171ea3e67d..4a9392b987a893d503ad849fe87c6ae7e104ab81 100644
--- a/pkg/front_end/testcases/static_setter.dart
+++ b/pkg/front_end/testcases/static_setter.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.
+
 class Foo {}
 
 set foo(x) {}