Get rid of all the library tags.

test/transformer/exclusion/works_on_dart2js_test.dart

 // Copyright (c) 2014, 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_stream.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 import '../../serve/utils.dart';
 
 main() {
   integration("works on the dart2js transformer", () {
     serveBarback();
@@ skipping 27 matching lines @@
     requestShouldSucceed("b.dart.js", isNot(isEmpty));
     server.stdout.expect(consumeThrough(emitsLines(
         "[Info from Dart2JS]:\n"
         "Compiling myapp|web/b.dart...")));
     server.stdout.expect(consumeThrough("Build completed successfully"));
 
     requestShould404("c.dart.js");
     endPubServe();
   });
 }