Get rid of all the library tags.

test/snapshot/upgrades_snapshot_for_dependency_test.dart

 // Copyright (c) 2014, 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.
 
-library pub_tests;
-
 import 'package:path/path.dart' as p;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 main() {
   integration("upgrades a snapshot when a dependency is upgraded", () {
     servePackages((builder) {
       builder.serve("foo", "1.2.3", pubspec: {
@@ skipping 30 matching lines @@
 
     d.dir(p.join(appPath, '.pub', 'bin', 'foo'), [
       d.matcherFile('hello.dart.snapshot', contains('hello 2!'))
     ]).validate();
 
     var process = pubRun(args: ['foo:hello']);
     process.stdout.expect("hello 2!");
     process.shouldExit();
   });
 }