Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/global/run/errors_if_outside_bin_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:path/path.dart' as p;
-
-import '../../../lib/src/exit_codes.dart' as exit_codes;
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration('errors if the script is in a subdirectory.', () {
-    servePackages((builder) {
-      builder.serve(
-          "foo",
-          "1.0.0",
-          contents: [
-              d.dir("example", [d.file("script.dart", "main(args) => print('ok');")])]);
-    });
-
-    schedulePub(args: ["global", "activate", "foo"]);
-    schedulePub(args: ["global", "run", "foo:example/script"], error: """
-Cannot run an executable in a subdirectory of a global package.
-
-Usage: pub global run <package>:<executable> [args...]
--h, --help    Print this usage information.
-    --mode    Mode to run transformers in.
-              (defaults to "release")
-
-Run "pub help" to see global options.
-""", exitCode: exit_codes.USAGE);
-  });
-}