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

sdk/lib/_internal/pub_generated/test/cache/add/adds_latest_version_test.dart

 // Copyright (c) 2014, 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.
 
 library pub_tests;
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration('adds the latest stable version of the package', () {
     servePackages((builder) {
       builder.serve("foo", "1.2.2");
       builder.serve("foo", "1.2.3");
       builder.serve("foo", "1.2.4-dev");
     });
 
-    schedulePub(args: ["cache", "add", "foo"],
+    schedulePub(
+        args: ["cache", "add", "foo"],
         output: 'Downloading foo 1.2.3...');
 
-    d.cacheDir({"foo": "1.2.3"}).validate();
+    d.cacheDir({
+      "foo": "1.2.3"
+    }).validate();
   });
 }