Update reason after full paint invalidation

third_party/WebKit/LayoutTests/paint/invalidation/multicol-with-text-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutMultiColumnFlowThread (anonymous)",
           "rect": [8, 8, 630, 20],
           "reason": "border box change"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [488, 8, 80, 20],
-          "reason": "layoutObject insertion"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutMultiColumnFlowThread (anonymous)",
       "reason": "border box change"
     },
     {
@@ skipping 20 matching lines @@
       "object": "LayoutText #text",
       "reason": "layoutObject insertion"
     },
     {
       "object": "InlineTextBox 'PASS'",
       "reason": "layoutObject insertion"
     }
   ]
 }