Get rid of all the library tags.

test/serve/404_page_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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.
 
-library pub_tests;
-
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
   setUp(() {
     d.dir(appPath, [
       d.appPubspec()
@@ skipping 22 matching lines @@
     scheduleRequest("packages").then((response) {
       expect(response.statusCode, equals(404));
 
       // Should mention the asset that can't be found.
       expect(response.body, contains('"packages"'));
     });
 
     endPubServe();
   });
 }