Simplify incremental paint invalidation

third_party/WebKit/LayoutTests/paint/invalidation/table-section-repaint-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutTableCell TD class='half'",
@@ skipping 87 matching lines @@
         },
         {
           "object": "LayoutTableCell TD class='red half'",
           "rect": [8, 8, 60, 30],
           "reason": "bounds change"
         },
         {
           "object": "LayoutTable TABLE",
           "rect": [8, 372, 60, 19],
           "reason": "incremental"
-        },
-        {
-          "object": "LayoutTable TABLE",
-          "rect": [8, 376, 60, 15],
-          "reason": "incremental"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow CAPTION id='caption1' class='blue half'",
       "reason": "became invisible"
     },
     {
@@ skipping 68 matching lines @@
       "object": "LayoutTableRow TR",
       "reason": "location change"
     },
     {
       "object": "LayoutTableCell TD class='half'",
       "reason": "bounds change"
     }
   ]
 }