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

sdk/lib/_internal/pub_generated/test/global/activate/constraint_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 'package:scheduled_test/scheduled_test.dart';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration('chooses the highest version that matches the constraint', () {
     servePackages((builder) {
       builder.serve("foo", "1.0.0");
       builder.serve("foo", "1.0.1");
       builder.serve("foo", "1.1.0");
       builder.serve("foo", "1.2.3");
     });
 
     schedulePub(args: ["global", "activate", "foo", "<1.1.0"]);
 
-    d.dir(cachePath, [
-      d.dir('global_packages', [
-        d.dir('foo', [d.matcherFile('pubspec.lock', contains('1.0.1'))])
-      ])
-    ]).validate();
+    d.dir(
+        cachePath,
+        [
+            d.dir(
+                'global_packages',
+                [
+                    d.dir('foo', [d.matcherFile('pubspec.lock', contains('1.0.1'))])])]).validate();
   });
 }