pkg/scheduled_test: fix analyzer hints

test/scheduled_test/current_schedule_errors_test.dart

Index: test/scheduled_test/current_schedule_errors_test.dart
diff --git a/test/scheduled_test/current_schedule_errors_test.dart b/test/scheduled_test/current_schedule_errors_test.dart
index 6585a1e28a0148783890e594c3619a6b57503877..eacdbe83bf8816a599b10b76cde762e4066a0ea2 100644
--- a/test/scheduled_test/current_schedule_errors_test.dart
+++ b/test/scheduled_test/current_schedule_errors_test.dart
@@ -2,11 +2,8 @@
 // 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 'dart:async';
-
 import 'package:scheduled_test/scheduled_test.dart';
 
-import 'package:metatest/metatest.dart';
 import '../utils.dart';
 
 void main() {