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

sdk/lib/_internal/pub_generated/test/transformer/dart2js_transformer_before_another_transformer_test.dart

Index: sdk/lib/_internal/pub_generated/test/transformer/dart2js_transformer_before_another_transformer_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/transformer/dart2js_transformer_before_another_transformer_test.dart b/sdk/lib/_internal/pub_generated/test/transformer/dart2js_transformer_before_another_transformer_test.dart
deleted file mode 100644
index 5be8957e92961cb9e03f238ab412fedb6e7a3485..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/test/transformer/dart2js_transformer_before_another_transformer_test.dart
+++ /dev/null
@@ -1,30 +0,0 @@
-// 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';
-
-// Regression test for issue 21726.
-main() {
-  initConfig();
-  withBarbackVersions("any", () {
-    integration("runs a dart2js transformer before a local transformer", () {
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "transformers": [r"$dart2js", "myapp/src/transformer"]
-        }),
-            d.dir("lib", [d.dir("src", [d.file("transformer.dart", REWRITE_TRANSFORMER)])]),
-            d.dir("web", [d.file("foo.txt", "foo")])]).create();
-
-      createLockFile('myapp', pkg: ['barback']);
-
-      pubServe();
-      requestShouldSucceed("foo.out", "foo.out");
-      endPubServe();
-    });
-  });
-}