Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/get/git/check_out_with_trailing_slash_test.dart

-// Copyright (c) 2012, 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 'package:scheduled_test/scheduled_test.dart';
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  group("(regression)", () {
-    integration('checks out a package from Git with a trailing slash', () {
-      ensureGit();
-
-      d.git(
-          'foo.git',
-          [d.libDir('foo'), d.libPubspec('foo', '1.0.0')]).create();
-
-      d.appDir({
-        "foo": {
-          "git": "../foo.git/"
-        }
-      }).create();
-
-      pubGet();
-
-      d.dir(
-          cachePath,
-          [
-              d.dir(
-                  'git',
-                  [
-                      d.dir('cache', [d.gitPackageRepoCacheDir('foo')]),
-                      d.gitPackageRevisionCacheDir('foo')])]).validate();
-
-      d.dir(
-          packagesPath,
-          [d.dir('foo', [d.file('foo.dart', 'main() => "foo";')])]).validate();
-    });
-  });
-}