Put "packages" directories in "benchmark".

sdk/lib/_internal/pub/test/validator/directory_test.dart

 // Copyright (c) 2013, 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:pathos/path.dart' as path;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../lib/src/entrypoint.dart';
 import '../../lib/src/validator.dart';
 import '../../lib/src/validator/directory.dart';
@@ skipping 17 matching lines @@
         d.dir("foo", [d.dir("tools")])
       ]).create();
       expectNoValidationError(directory);
     });
   });
 
   group('should consider a package invalid if it has a top-level directory '
       'named', () {
     setUp(d.validPackage.create);
 
-    var names = ["tools", "tests", "docs", "examples", "sample", "samples"];
+    var names = [
+      "benchmarks", "docs", "examples", "sample", "samples", "tests", "tools"
+    ];
+
     for (var name in names) {
       integration('"$name"', () {
         d.dir(appPath, [d.dir(name)]).create();
         expectValidationWarning(directory);
       });
     }
   });
 }