Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/get/path/shared_dependency_symlink_test.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 d.file.
-
-import 'package:path/path.dart' as path;
-
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration("shared dependency with symlink", () {
-    d.dir(
-        "shared",
-        [d.libDir("shared"), d.libPubspec("shared", "0.0.1")]).create();
-
-    d.dir("foo", [d.libDir("foo"), d.libPubspec("foo", "0.0.1", deps: {
-        "shared": {
-          "path": "../shared"
-        }
-      })]).create();
-
-    d.dir("bar", [d.libDir("bar"), d.libPubspec("bar", "0.0.1", deps: {
-        "shared": {
-          "path": "../link/shared"
-        }
-      })]).create();
-
-    d.dir(appPath, [d.appPubspec({
-        "foo": {
-          "path": "../foo"
-        },
-        "bar": {
-          "path": "../bar"
-        }
-      })]).create();
-
-    d.dir("link").create();
-    scheduleSymlink("shared", path.join("link", "shared"));
-
-    pubGet();
-
-    d.dir(
-        packagesPath,
-        [
-            d.dir("foo", [d.file("foo.dart", 'main() => "foo";')]),
-            d.dir("bar", [d.file("bar.dart", 'main() => "bar";')]),
-            d.dir("shared", [d.file("shared.dart", 'main() => "shared";')])]).validate();
-  });
-}