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

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": "forced by layout"
+          "reason": "border box change"
         },
         {
           "object": "LayoutText #text",
           "rect": [488, 8, 80, 20],
           "reason": "layoutObject insertion"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutMultiColumnFlowThread (anonymous)",
-      "reason": "forced by layout"
+      "reason": "border box change"
     },
     {
       "object": "RootInlineBox",
-      "reason": "forced by layout"
+      "reason": "border box change"
     },
     {
       "object": "LayoutBR BR",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "InlineTextBox '\n'",
-      "reason": "forced by layout"
-    },
-    {
-      "object": "LayoutBR BR",
       "reason": "forced by layout"
     },
     {
       "object": "InlineTextBox '\n'",
       "reason": "forced by layout"
     },
     {
       "object": "LayoutBR BR",
       "reason": "forced by layout"
     },
     {
       "object": "InlineTextBox '\n'",
       "reason": "forced by layout"
     },
     {
       "object": "LayoutText #text",
       "reason": "layoutObject insertion"
     },
     {
       "object": "InlineTextBox 'PASS'",
       "reason": "layoutObject insertion"
     }
   ]
 }