pkg: analysis aided cleanup

pkg/scheduled_test/test/scheduled_test/set_up_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 'dart:async';
-import 'dart:io';
-
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../metatest.dart';
 import '../utils.dart';
 
 void main() {
   setUpTimeout();
 
   expectTestsPass('setUp is run before each test', () {
     var setUpRun = false;
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       });
     });
 
     test('top', () {
       expect(setUpOuterRun, isFalse);
       expect(setUpInnerRun, isFalse);
     });
   });
 
 }