Update unittest to new package layout.

pkg/unittest/test/unittest_test.dart

 // Copyright (c) 2012, 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.
 
 // TODO(gram):
 // Unfortunately I can't seem to test anything that involves timeouts, e.g.
 // insufficient callbacks, because the timeout is controlled externally
 // (test.dart?), and we would need to use a shorter timeout for the inner tests
 // so the outer timeout doesn't fire. So I removed all such tests.
 // I'd like to revisit this at some point.
 
 #library('unittestTest');
 #import('dart:isolate');
-#import('../../../pkg/unittest/unittest.dart');
+#import('../../../pkg/unittest/lib/unittest.dart');
 
 var tests; // array of test names
 var expected; // array of test expected results (from buildStatusString)
 var actual; // actual test results (from buildStatusString in config.onDone)
 var _testconfig; // test configuration to capture onDone
 
 _defer(void fn()) {
   // Exploit isolate ports as a platform-independent mechanism to queue a
   // message at the end of the event loop. Stolen from unittest.dart.
   final port = new ReceivePort();
@@ skipping 164 matching lines @@
     buildStatusString(1, 0, 0, tests[9], 10),
     buildStatusString(0, 1, 0, tests[10], message: 'Caught error!'),
     buildStatusString(1, 0, 1, 'testOne', message: 'Callback called after already being marked as done (1).:testTwo:')
   ];
 
   actual = [];
 
   nextTest(0);
 }