Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/upgrade/report/shows_number_of_changed_dependencies_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",
-      () {
-    servePackages((builder) {
-      builder.serve("a", "1.0.0");
-      builder.serve("b", "1.0.0");
-      builder.serve("c", "2.0.0");
-    });
-
-    d.appDir({
-      "a": "any"
-    }).create();
-
-    // One dependency changed.
-    pubUpgrade(output: new RegExp(r"Changed 1 dependency!$"));
-
-    // Remove one and add two.
-    d.appDir({
-      "b": "any",
-      "c": "any"
-    }).create();
-
-    pubUpgrade(output: new RegExp(r"Changed 3 dependencies!$"));
-
-    // Don't change anything.
-    pubUpgrade(output: new RegExp(r"No dependencies changed.$"));
-  });
-}