Get rid of all the library tags.

test/transformer/loads_a_declaring_aggregate_transformer_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 '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 const AGGREGATE_TRANSFORMER = """
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:path/path.dart' as p;
 
@@ skipping 46 matching lines @@
 
     pubGet();
     var server = pubServe();
     // The transformer should preserve laziness.
     server.stdout.expect("Build completed successfully");
 
     requestShouldSucceed("out.final", "bar.out\nfoo.out");
     endPubServe();
   });
 }