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

sdk/lib/_internal/pub_generated/test/barback/fails_if_dir_arg_does_not_exist_test.dart

 // Copyright (c) 2014, 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 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.dir(appPath, [
-      d.appPubspec(),
-      d.dir("bar", [
-        d.file("file.txt", "contents")
-      ])
-    ]).create();
+    d.dir(
+        appPath,
+        [d.appPubspec(), d.dir("bar", [d.file("file.txt", "contents")])]).create();
   });
 
-  pubBuildAndServeShouldFail("if a specified directory doesn't exist",
+  pubBuildAndServeShouldFail(
+      "if a specified directory doesn't exist",
       args: ["foo", "bar", "baz"],
       error: 'Directories "foo" and "baz" do not exist.',
       exitCode: exit_codes.DATA);
 }