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

sdk/lib/_internal/pub_generated/test/dart2js/minifies_in_release_mode_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.
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 main() {
   initConfig();
   integration("generates minified JS in release mode", () {
-    d.dir(appPath, [
-      d.appPubspec(),
-      d.dir("web", [
-        d.file("main.dart", "void main() => print('hello');")
-      ])
-    ]).create();
+    d.dir(
+        appPath,
+        [
+            d.appPubspec(),
+            d.dir(
+                "web",
+                [d.file("main.dart", "void main() => print('hello');")])]).create();
 
     pubServe(args: ["--mode", "release"]);
     requestShouldSucceed("main.dart.js", isMinifiedDart2JSOutput);
     endPubServe();
   });
 }