Simplify incremental paint invalidation

third_party/WebKit/LayoutTests/paint/invalidation/table/cached-change-colgroup-border-width-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutTableCol COLGROUP id='colgroup'",
@@ skipping 47 matching lines @@
         },
         {
           "object": "LayoutTableCell TD",
           "rect": [116, 9, 54, 50],
           "reason": "bounds change"
         },
         {
           "object": "LayoutTable TABLE",
           "rect": [169, 8, 5, 102],
           "reason": "incremental"
-        },
-        {
-          "object": "LayoutTable TABLE",
-          "rect": [170, 8, 4, 102],
-          "reason": "incremental"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutTableCell TD",
       "reason": "style change"
     },
     {
@@ skipping 44 matching lines @@
       "object": "LayoutTableCell TD",
       "reason": "bounds change"
     },
     {
       "object": "LayoutTableCell TD",
       "reason": "bounds change"
     }
   ]
 }