Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/global/binstubs/outdated_snapshot_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 'dart:io';
-
-import 'package:path/path.dart' as p;
-import 'package:scheduled_test/scheduled_process.dart';
-import 'package:scheduled_test/scheduled_stream.dart';
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../../../lib/src/io.dart';
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-import 'utils.dart';
-
-main() {
-  initConfig();
-  integration("a binstub runs 'pub global run' for an outdated snapshot", () {
-    servePackages((builder) {
-      builder.serve("foo", "1.0.0", pubspec: {
-        "executables": {
-          "foo-script": "script"
-        }
-      },
-          contents: [
-              d.dir("bin", [d.file("script.dart", "main(args) => print('ok \$args');")])]);
-    });
-
-    schedulePub(args: ["global", "activate", "foo"]);
-
-    d.dir(
-        cachePath,
-        [
-            d.dir(
-                'global_packages',
-                [
-                    d.dir(
-                        'foo',
-                        [d.dir('bin', [d.outOfDateSnapshot('script.dart.snapshot')])])])]).create();
-
-    var process = new ScheduledProcess.start(
-        p.join(sandboxDir, cachePath, "bin", binStubName("foo-script")),
-        ["arg1", "arg2"],
-        environment: getEnvironment());
-
-    process.stderr.expect(startsWith("Wrong script snapshot version"));
-    process.stdout.expect(consumeThrough("ok [arg1, arg2]"));
-    process.shouldExit();
-
-    d.dir(
-        cachePath,
-        [
-            d.dir(
-                'global_packages/foo/bin',
-                [
-                    d.binaryMatcherFile(
-                        'script.dart.snapshot',
-                        isNot(
-                            equals(readBinaryFile(testAssetPath('out-of-date.snapshot')))))])]).validate();
-  });
-}