Don't include nested outlines when computing repaint rects for SVG objects

LayoutTests/svg/repaint/shape-with-nested-outline-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
-        [8, 8, 30, 30]
+        [108, 108, 300, 300]
       ]
     }
   ]
 }