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

sdk/lib/_internal/pub_generated/test/build/allows_arbitrary_modes_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';
 
 const TRANSFORMER = """
@@ skipping 13 matching lines @@
       transform.addOutput(new Asset.fromString(id, settings.mode.toString()));
     });
   }
 }
 """;
 
 main() {
   initConfig();
   withBarbackVersions("any", () {
     integration("allows user-defined mode names", () {
-      d.dir(appPath, [
-        d.pubspec({
+      d.dir(appPath, [d.pubspec({
           "name": "myapp",
           "transformers": ["myapp/src/transformer"]
         }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", TRANSFORMER)
-        ])]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
-        ])
-      ]).create();
+            d.dir("lib", [d.dir("src", [d.file("transformer.dart", TRANSFORMER)])]),
+            d.dir("web", [d.file("foo.txt", "foo")])]).create();
 
       createLockFile('myapp', pkg: ['barback']);
 
       schedulePub(args: ["build", "--mode", "depeche"]);
 
-      d.dir(appPath, [
-        d.dir('build', [
-          d.dir('web', [
-            d.file('foo.out', 'depeche')
-          ])
-        ])
-      ]).validate();
+      d.dir(
+          appPath,
+          [d.dir('build', [d.dir('web', [d.file('foo.out', 'depeche')])])]).validate();
     });
   });
 }