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

sdk/lib/_internal/pub_generated/test/get/git/check_out_transitive_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 '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration('checks out packages transitively from Git', () {
-    ensureGit();
-
-    d.git('foo.git', [d.libDir('foo'), d.libPubspec('foo', '1.0.0', deps: {
-        "bar": {
-          "git": "../bar.git"
-        }
-      })]).create();
-
-    d.git('bar.git', [d.libDir('bar'), d.libPubspec('bar', '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.gitPackageRepoCacheDir('bar')]),
-                    d.gitPackageRevisionCacheDir('foo'),
-                    d.gitPackageRevisionCacheDir('bar')])]).validate();
-
-    d.dir(
-        packagesPath,
-        [
-            d.dir('foo', [d.file('foo.dart', 'main() => "foo";')]),
-            d.dir('bar', [d.file('bar.dart', 'main() => "bar";')])]).validate();
-  });
-}