No need to force relayout of children when page logical height changes.

third_party/WebKit/LayoutTests/platform/mac/paint/invalidation/multicol-repaint-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
-          "object": "LayoutMultiColumnFlowThread (anonymous)",
-          "rect": [9, 9, 400, 100],
-          "reason": "forced by layout"
-        },
-        {
           "object": "LayoutInline SPAN id='a'",
           "rect": [234, 9, 300, 59],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutText #text",
           "rect": [234, 15, 300, 50],
           "reason": "full"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [9, 9, 13, 59],
-          "reason": "forced by layout"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
-      "object": "LayoutMultiColumnFlowThread (anonymous)",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "RootInlineBox",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "LayoutText #text",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "InlineTextBox '\u00A0'",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "LayoutBR BR",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "InlineTextBox '\n'",
-      "reason": "forced by layout"
-    },
-    {
       "object": "LayoutInline SPAN id='a'",
       "reason": "forced by layout"
     },
     {
       "object": "InlineFlowBox",
       "reason": "forced by layout"
     },
     {
       "object": "LayoutText #text",
       "reason": "full"
     },
     {
       "object": "InlineTextBox 'XXXXXX'",
       "reason": "full"
     }
   ]
 }