Update unittest to new package layout.

pkg/logging/test/logging_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.
 
 
 #library('logging_test');
 
 // TODO(rnystrom): Use "package:" import when test.dart supports it (#4968).
 #import('../lib/logging.dart');
-#import('../../../pkg/unittest/unittest.dart');
+#import('../../../pkg/unittest/lib/unittest.dart');
 
 main() {
   test('level comparison is a valid comparator', () {
     var level1 = const Level('NOT_REAL1', 253);
     expect(level1 == level1);
     expect(level1 <= level1);
     expect(level1 >= level1);
     expect(level1 < level1, isFalse);
     expect(level1 > level1, isFalse);
 
@@ skipping 307 matching lines @@
             'SHOUT: 10']));
 
       expect(cMessages, equals([
             // 1 - 7 are lower in the hierarchy
             // 'FINE: 8' is not loggable
             'WARNING: 9',
             'SHOUT: 10']));
     });
   });
 }