Fix yet another bad copyright year in a test.

tests/language/generic_function_typedef2_test.dart

Index: tests/language/generic_function_typedef2_test.dart
diff --git a/tests/language/generic_function_typedef2_test.dart b/tests/language/generic_function_typedef2_test.dart
index 8ca5ee49d6be5c1f94971e49f8d76308bf9534da..1822971268cf6d5e20b84729afcba15df961ed7e 100644
--- a/tests/language/generic_function_typedef2_test.dart
+++ b/tests/language/generic_function_typedef2_test.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// 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.
 // Dart test for a function type test that cannot be eliminated at compile time.