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

sdk/lib/_internal/pub_generated/test/global/activate/reactivating_git_upgrades_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.
-
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration('ignores previously activated git commit', () {
-    ensureGit();
-
-    d.git('foo.git', [d.libPubspec("foo", "1.0.0")]).create();
-
-    schedulePub(
-        args: ["global", "activate", "-sgit", "../foo.git"],
-        output: allOf(
-            startsWith('Resolving dependencies...\n' '+ foo 1.0.0 from git ../foo.git at '),
-            // Specific revision number goes here.
-    endsWith(
-        'Precompiling executables...\n' 'Loading source assets...\n'
-            'Activated foo 1.0.0 from Git repository "../foo.git".')));
-
-    d.git('foo.git', [d.libPubspec("foo", "1.0.1")]).commit();
-
-    // Activating it again pulls down the latest commit.
-    schedulePub(
-        args: ["global", "activate", "-sgit", "../foo.git"],
-        output: allOf(
-            startsWith(
-                'Package foo is currently active from Git repository ' '"../foo.git".\n'
-                    'Resolving dependencies...\n' '+ foo 1.0.1 from git ../foo.git at '),
-            // Specific revision number goes here.
-    endsWith(
-        'Precompiling executables...\n' 'Loading source assets...\n'
-            'Activated foo 1.0.1 from Git repository "../foo.git".')));
-  });
-}