Revert "Revert "Use native async/await support in pub.""

sdk/lib/_internal/pub_generated/test/oauth2/with_server_rejected_credentials_authenticates_again_test.dart

-// Copyright (c) 2012, 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:convert';
-
-import 'package:scheduled_test/scheduled_server.dart';
-import 'package:scheduled_test/scheduled_test.dart';
-import 'package:shelf/shelf.dart' as shelf;
-
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-
-main() {
-  initConfig();
-  integration(
-      'with server-rejected credentials, authenticates again and saves '
-          'credentials.json',
-      () {
-    d.validPackage.create();
-    var server = new ScheduledServer();
-    d.credentialsFile(server, 'access token').create();
-    var pub = startPublish(server);
-
-    confirmPublish(pub);
-
-    server.handle('GET', '/api/packages/versions/new', (request) {
-      return new shelf.Response(401, body: JSON.encode({
-        'error': {
-          'message': 'your token sucks'
-        }
-      }), headers: {
-        'www-authenticate': 'Bearer error="invalid_token",'
-            ' error_description="your token sucks"'
-      });
-    });
-
-    pub.stderr.expect('OAuth2 authorization failed (your token sucks).');
-    pub.stdout.expect(startsWith('Uploading...'));
-    pub.kill();
-  });
-}