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

sdk/lib/_internal/pub_generated/test/transformer/loads_different_configurations_from_the_same_isolate_test.dart

-// Copyright (c) 2014, 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("loads different configurations from the same isolate", () {
-      // If different configurations are loaded from different isolates, a
-      // transformer can end up being loaded twice. It's even possible for the
-      // second load to use code that's transformed by the first, which is
-      // really bad. This tests sets up such a scenario.
-      //
-      // The foo package has two self-transformers: foo/first and foo/second,
-      // loaded in that order. This means that *no instances of foo/first*
-      // should ever have their code transformed by foo/second.
-      //
-      // The myapp package also has a reference to foo/first. This reference has
-      // a different configuration than foo's, which means that if it's loaded
-      // in a separate isolate, it will be loaded after all of foo's
-      // transformers have run. This means that foo/first.dart will have been
-      // transformed by foo/first and foo/second, causing it to have different
-      // code than the previous instance. This tests asserts that that doesn't
-      // happen.
-
-      d.dir("foo", [d.pubspec({
-          "name": "foo",
-          "version": "1.0.0",
-          "transformers": [{
-              "foo/first": {
-                "addition": " in foo"
-              }
-            }, "foo/second"]
-        }),
-            d.dir(
-                "lib",
-                [
-                    d.file("first.dart", dartTransformer('foo/first')),
-                    d.file("second.dart", dartTransformer('foo/second'))])]).create();
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "transformers": [{
-              "foo/first": {
-                "addition": " in myapp",
-                "\$include": "web/first.dart"
-              }
-            }, {
-              "foo/second": {
-                "\$include": "web/second.dart"
-              }
-            }],
-          "dependencies": {
-            'foo': {
-              'path': '../foo'
-            }
-          }
-        }),
-            d.dir("web", [// This is transformed by foo/first. It's used to see which
-          // transformers ran on foo/first.
-          d.file("first.dart", 'const TOKEN = "myapp/first";'),
-              // This is transformed by foo/second. It's used to see which
-          // transformers ran on foo/second.
-          d.file("second.dart", 'const TOKEN = "myapp/second";')])]).create();
-
-      createLockFile('myapp', sandbox: ['foo'], pkg: ['barback']);
-
-      pubServe();
-
-      // The version of foo/first used on myapp should have myapp's
-      // configuration and shouldn't be transformed by foo/second.
-      requestShouldSucceed(
-          "first.dart",
-          'const TOKEN = "(myapp/first, foo/first in myapp)";');
-
-      // foo/second should be transformed by only foo/first.
-      requestShouldSucceed(
-          "second.dart",
-          'const TOKEN = "(myapp/second, (foo/second, foo/first in foo))";');
-
-      endPubServe();
-    });
-  });
-}