Start pulling pub from its own repo.

sdk/lib/_internal/pub/test/serve/gets_first_if_no_lockfile_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.
-
-library pub_tests;
-
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import 'utils.dart';
-
-main() {
-  initConfig();
-  integration("gets first if there is no lockfile", () {
-    d.dir("foo", [
-      d.libPubspec("foo", "0.0.1"),
-      d.libDir("foo")
-    ]).create();
-
-    d.appDir({
-      "foo": {"path": "../foo"}
-    }).create();
-
-    pubServe(shouldGetFirst: true);
-    requestShouldSucceed("packages/foo/foo.dart", 'main() => "foo";');
-    endPubServe();
-  });
-}