test rename overhaul: step 6 - isolate tests

tests/isolate/mixed2_test.dart

 // Copyright (c) 2011, 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.
 
 // Dart test program for testing that heavy and light isolates can be mixed.
 
 #library('Mixed2Test');
 #import("dart:isolate");
-#import('../../../lib/unittest/unittest.dart');
+#import('../../lib/unittest/unittest.dart');
 
 // We want to send a message from the main-isolate to a chain of different
 // isolates and then get a reply back.
 // In the following description heavy2 is not used, because it is shut down
 // just after heaving created heavy2.light1,2 and light3.
 // main->
 //   heavy1->heavy1.light1->heavy1.light2->heavy1.light3->
 //   heavy2.light1->heavy2.light2->heavy2.light3->
 //   heavy3->heavy3.pong
 
@@ skipping 104 matching lines @@
             // Start the chain-message.
             heavy1Port.call(1).then(expectAsync1((result) {
               Expect.equals(6531, result);
             }));
           }));
         }));
       }));
     }));
   });
 }