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

sdk/lib/_internal/pub_generated/test/upgrade/report/does_not_show_newer_versions_for_locked_packages_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.
 
 library pub_tests;
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
-  integration("does not show how many newer versions are available for "
-      "packages that are locked and not being upgraded", () {
+  integration(
+      "does not show how many newer versions are available for "
+          "packages that are locked and not being upgraded",
+      () {
     servePackages((builder) {
       builder.serve("not_upgraded", "1.0.0");
       builder.serve("not_upgraded", "2.0.0");
       builder.serve("not_upgraded", "3.0.0-dev");
       builder.serve("upgraded", "1.0.0");
       builder.serve("upgraded", "2.0.0");
       builder.serve("upgraded", "3.0.0-dev");
     });
 
     // Constraint everything to the first version.
@@ skipping 11 matching lines @@
     }).create();
 
     // Only upgrade "upgraded".
     pubUpgrade(args: ["upgraded"], output: new RegExp(r"""
 Resolving dependencies\.\.\..*
   not_upgraded 1\.0\.0
 . upgraded 2\.0\.0 \(was 1\.0\.0\) \(3\.0\.0-dev available\)
 """, multiLine: true));
   });
 }