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

sdk/lib/_internal/pub_generated/test/run/doesnt_load_an_unnecessary_transformer_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 '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 const TRANSFORMER = """
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 
 class BrokenTransformer extends Transformer {
   RewriteTransformer.asPlugin() {
     throw 'This transformer is broken!';
   }
 
   String get allowedExtensions => '.txt';
 
   void apply(Transform transform) {}
 }
 """;
 
 main() {
   initConfig();
   withBarbackVersions("any", () {
     integration("doesn't load an unnecessary transformer", () {
-      d.dir(appPath, [
-        d.pubspec({
+      d.dir(appPath, [d.pubspec({
           "name": "myapp",
-          "transformers": [
-            {"myapp/src/transformer": {r"$include": "lib/myapp.dart"}}
-          ]
+          "transformers": [{
+              "myapp/src/transformer": {
+                r"$include": "lib/myapp.dart"
+              }
+            }]
         }),
-        d.dir("lib", [
-          d.file("myapp.dart", ""),
-          d.dir("src", [d.file("transformer.dart", TRANSFORMER)])
-        ]),
-        d.dir("bin", [
-          d.file("hi.dart", "void main() => print('Hello!');")
-        ])
-      ]).create();
+            d.dir(
+                "lib",
+                [
+                    d.file("myapp.dart", ""),
+                    d.dir("src", [d.file("transformer.dart", TRANSFORMER)])]),
+            d.dir("bin", [d.file("hi.dart", "void main() => print('Hello!');")])]).create();
 
       createLockFile('myapp', pkg: ['barback']);
 
       // This shouldn't load the transformer, since it doesn't transform
       // anything that the entrypoint imports. If it did load the transformer,
       // we'd know since it would throw an exception.
       var pub = pubRun(args: ["hi"]);
       pub.stdout.expect("Hello!");
       pub.shouldExit();
     });
   });
 }