Get rid of all the library tags.

test/serve/defaults_to_debug_mode_test.dart

Index: test/serve/defaults_to_debug_mode_test.dart
diff --git a/test/serve/defaults_to_debug_mode_test.dart b/test/serve/defaults_to_debug_mode_test.dart
index 651bfaa3a03c3c7564df9bf4f92c914b86d104fc..ee97c0f3a1240d871e77db54dc82be344ca1764a 100644
--- a/test/serve/defaults_to_debug_mode_test.dart
+++ b/test/serve/defaults_to_debug_mode_test.dart
@@ -2,8 +2,6 @@
 // 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.
 
-library pub_tests;
-
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';