Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/lish/cloud_storage_upload_provides_an_error_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 'package:scheduled_test/scheduled_test.dart';
-import 'package:scheduled_test/scheduled_server.dart';
-import 'package:shelf/shelf.dart' as shelf;
-
-import '../../lib/src/io.dart';
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import 'utils.dart';
-
-main() {
-  initConfig();
-  setUp(d.validPackage.create);
-
-  integration('cloud storage upload provides an error', () {
-    var server = new ScheduledServer();
-    d.credentialsFile(server, 'access token').create();
-    var pub = startPublish(server);
-
-    confirmPublish(pub);
-    handleUploadForm(server);
-
-    server.handle('POST', '/upload', (request) {
-      return drainStream(request.read()).then((_) {
-        return new shelf.Response.notFound(
-            '<Error><Message>Your request sucked.</Message></Error>',
-            headers: {
-          'content-type': 'application/xml'
-        });
-      });
-    });
-
-    // TODO(nweiz): This should use the server's error message once the client
-    // can parse the XML.
-    pub.stderr.expect('Failed to upload the package.');
-    pub.shouldExit(1);
-  });
-}