Make unittest follow the new package layout.

tests/html/inner_frame_test.dart

 #library('InnerFrameTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
+#import('../../pkg/unittest/lib/unittest.dart');
+#import('../../pkg/unittest/lib/html_config.dart');
 #import('dart:html');
 
 main() {
   if (window != window.top) {
     // Child frame.
 
     // The child's frame should not be able to access its parent's
     // document.
 
     // Check window.frameElement.
@@ skipping 40 matching lines @@
       Expect.isNull(div);
     });
 
   test('top', () {
       var div = document.query('#illegalTop');
 
       // Ensure that this parent frame was not modified by its child.
       Expect.isNull(div);
     });
 }