Fix some tests that were broken in the library tag removal.

test/dart2js/compiles_generated_file_from_dependency_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.
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 main() {
   integration("compiles a Dart file that imports a generated file in another "
               "package to JS", () {
     serveBarback();
 
     d.dir("foo", [
       d.pubspec({
         "name": "foo",
         "version": "0.0.1",
         "transformers": ["foo/transformer"],
         "dependencies": {"barback": "any"}
       }),
       d.dir("lib", [
         d.file("foo.dart", """
+const TOKEN = "before";
 foo() => TOKEN;
 """),
         d.file("transformer.dart", dartTransformer("munge"))
       ])
     ]).create();
 
     d.dir(appPath, [
       d.appPubspec({
         "foo": {
           "path": "../foo"
         }
       }),
       d.dir("web", [
         d.file("main.dart", """
 import "package:foo/foo.dart";
 main() => print(foo());
 """)
       ])
     ]).create();
 
     pubGet();
     pubServe();
     requestShouldSucceed("main.dart.js", contains("(before, munge)"));
     endPubServe();
   });
 }