Fix a bunch of pub tests that started running "pub get".

test/barback/directory_args_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.
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
@@ skipping 20 matching lines @@
         d.dir('foo', [
           d.file('file.txt', 'foo')
         ]),
         d.nothing('test'),
         d.nothing('web')
       ])
     ]).validate();
   });
 
   integration("serves only the given directories", () {
-    pubServe(args: ["foo", "bar"]);
+    pubServe(args: ["foo", "bar"], shouldGetFirst: true);
 
     requestShouldSucceed("file.txt", "bar", root: "bar");
     requestShouldSucceed("file.txt", "foo", root: "foo");
     expectNotServed("test");
     expectNotServed("web");
 
     endPubServe();
   });
 }