Use ".."-style imports in scheduled_test.

pkg/scheduled_test/lib/src/schedule.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.
 
 library schedule;
 
 import 'dart:async';
 import 'dart:collection';
 
-import 'package:unittest/unittest.dart' as unittest;
+import '../../../../pkg/unittest/lib/unittest.dart' as unittest;
 
 import 'mock_clock.dart' as mock_clock;
 import 'schedule_error.dart';
 import 'substitute_future.dart';
 import 'task.dart';
 import 'value_future.dart';
 
 /// The schedule of tasks to run for a single test. This has three separate task
 /// queues: [tasks], [onComplete], and [onException]. It also provides
 /// visibility into the current state of the schedule.
@@ skipping 525 matching lines @@
           var childLines = child.toString().split("\n");
           lines.add("  $prefix ${childLines.first}");
           lines.addAll(childLines.skip(1).map((line) => "  | $line"));
         }
       }
 
       return lines.join("\n");
     }).join("\n");
   }
 }