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

sdk/lib/_internal/pub_generated/test/transformer/runs_one_third_party_transformer_on_another_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 file.
-
-library pub_tests;
-
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import '../serve/utils.dart';
-
-main() {
-  initConfig();
-  withBarbackVersions("any", () {
-    integration("runs one third-party transformer on another", () {
-      d.dir("foo", [d.pubspec({
-          "name": "foo",
-          "version": "1.0.0"
-        }),
-            d.dir("lib", [d.file("transformer.dart", dartTransformer('foo')),])]).create();
-
-      d.dir("bar", [d.pubspec({
-          "name": "bar",
-          "version": "1.0.0",
-          "transformers": ["foo/transformer"],
-          "dependencies": {
-            "foo": {
-              "path": "../foo"
-            }
-          }
-        }),
-            d.dir("lib", [d.file("transformer.dart", dartTransformer('bar')),])]).create();
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "transformers": ["bar/transformer"],
-          "dependencies": {
-            'bar': {
-              'path': '../bar'
-            }
-          }
-        }),
-            d.dir("web", [d.file("main.dart", 'const TOKEN = "main.dart";')])]).create();
-
-      createLockFile('myapp', sandbox: ['foo', 'bar'], pkg: ['barback']);
-
-      pubServe();
-      requestShouldSucceed(
-          "main.dart",
-          'const TOKEN = "(main.dart, (bar, foo))";');
-      endPubServe();
-    });
-  });
-}