Dirty nearby lineboxes if we layout a float rather than trying to work it out later

LayoutTests/platform/linux/fast/repaint/line-flow-with-floats-6-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
         [28, 363, 20, 19],
         [14, 363, 48, 64],
-        [8, 580, 418, 19]
+        [8, 320, 418, 79]
       ]
     }
   ]
 }