Sharing metatest logic between unittest and scheduled_test

pkg/scheduled_test/test/scheduled_test/abort_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:scheduled_test/scheduled_test.dart';
 
-import '../metatest.dart';
+import 'package:metatest/metatest.dart';
 import '../utils.dart';
 
-void main(_, message) {
+void main() => initTests(_test);
+
+void _test(message) {
   initMetatest(message);
 
   setUpTimeout();
 
   expectTestsPass("aborting the schedule before it's started running should "
       "cause no tasks to be run", () {
     test('test', () {
       schedule(() {
         throw 'error';
       });
@@ skipping 63 matching lines @@
   expectTestsFail("aborting the schedule after an out-of-band error should "
       "still surface the error", () {
     test('test', () {
       schedule(() {
         currentSchedule.signalError('error');
         currentSchedule.abort();
       });
     });
   });
 }