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

sdk/lib/_internal/pub_generated/test/list_package_dirs/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 d.file.
 
 import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 main() {
   initConfig();
   integration('with no lockfile, exits with error', () {
-    d.dir(appPath, [
-      d.appPubspec()
-    ]).create();
+    d.dir(appPath, [d.appPubspec()]).create();
 
-    schedulePub(args: ["list-package-dirs", "--format=json"],
-        outputJson: {
-          "error":
-            'Package "myapp" has no lockfile. Please run "pub get" first.'
-        },
-        exitCode: exit_codes.DATA);
+    schedulePub(args: ["list-package-dirs", "--format=json"], outputJson: {
+      "error": 'Package "myapp" has no lockfile. Please run "pub get" first.'
+    }, exitCode: exit_codes.DATA);
   });
-}
+}