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

sdk/lib/_internal/pub_generated/test/barback/fails_on_all_with_no_buildable_directories_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 '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
   initConfig();
 
   setUp(() {
     d.appDir().create();
   });
 
-  pubBuildAndServeShouldFail("on --all with no default source directories",
+  pubBuildAndServeShouldFail(
+      "on --all with no default source directories",
       args: ["--all"],
       error: 'There are no source directories present.\n'
-        'The default directories are "benchmark", "bin", "example", '
-        '"test" and "web".',
+          'The default directories are "benchmark", "bin", "example", '
+          '"test" and "web".',
       exitCode: exit_codes.DATA);
 }