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

sdk/lib/_internal/pub_generated/test/validator/dependency_override_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 '../../lib/src/entrypoint.dart';
 import '../../lib/src/validator.dart';
 import '../../lib/src/validator/dependency_override.dart';
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 Validator dependencyOverride(Entrypoint entrypoint) =>
     new DependencyOverrideValidator(entrypoint);
 
 main() {
   initConfig();
 
   integration('invalidates a package if it has dependency overrides', () {
-    d.dir(appPath, [
-      d.pubspec({
+    d.dir(appPath, [d.pubspec({
         "name": "myapp",
         "dependency_overrides": {
           "foo": "<3.0.0"
         }
-      })
-    ]).create();
+      })]).create();
 
     expectValidationError(dependencyOverride);
   });
 }