fix test_Handler_Box_draw in FF3, providing getComputedStyle with the correct number of arguments, this test still fails in IE8, no functional change

git-svn-id: http://svn.openlayers.org/trunk/openlayers@11862 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

tests/Handler/Box.html

@@ -20,7 +20,7 @@
     function test_Handler_Box_draw(t) {
         var testAll = true;
         if (document.defaultView && document.defaultView.getComputedStyle &&
-                    !document.defaultView.getComputedStyle(document.body)) {
+                    !document.defaultView.getComputedStyle(document.body, null)) {
             // we don't get dimensions for hidden frames in FF4, and our test
             // runs in a hidden frame.
             testAll = false;