Move pub into sdk/lib/_internal.

sdk/lib/_internal/pub/test/lish/archives_and_uploads_a_package_test.dart

 // Copyright (c) 2013, 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 'dart:json' as json;
 
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:scheduled_test/scheduled_server.dart';
 
 import '../descriptor.dart' as d;
@@ skipping 25 matching lines @@
     // gets echoed to the terminal. Do something better here?
     expect(pub.nextLine(), completion(equals(
         'Looks great! Are you ready to upload your package (y/n)?'
         ' Package test_pkg 1.0.0 uploaded!')));
     pub.shouldExit(0);
   });
 
   // TODO(nweiz): Once a multipart/form-data parser in Dart exists, we should
   // test that "pub lish" chooses the correct files to publish.
 }