No need to detect change in size when opting for PositionedMovementLayout

LayoutTests/fast/block/positioning/positioned-movement-layout-when-height-changes-expected.html

Index: LayoutTests/fast/block/positioning/positioned-movement-layout-when-height-changes-expected.html
diff --git a/LayoutTests/fast/block/positioning/positioned-movement-layout-when-width-changes-expected.html b/LayoutTests/fast/block/positioning/positioned-movement-layout-when-height-changes-expected.html
similarity index 76%
copy from LayoutTests/fast/block/positioning/positioned-movement-layout-when-width-changes-expected.html
copy to LayoutTests/fast/block/positioning/positioned-movement-layout-when-height-changes-expected.html
index a058aa3aef292e60425db54c55628084e43cca2b..23e87958706785a6edb0a3a5ac82bdf92c383623 100644
--- a/LayoutTests/fast/block/positioning/positioned-movement-layout-when-width-changes-expected.html
+++ b/LayoutTests/fast/block/positioning/positioned-movement-layout-when-height-changes-expected.html
@@ -3,11 +3,6 @@
     body {
         margin: 0;
     }
-    #top {
-        position: relative;
-        height: 500px;
-        width: 500px;
-    }
     #container {
         position: absolute;
         top: 0px;
@@ -18,10 +13,10 @@
     }
     #test {
         position: absolute;
-        top: 0px;
-        bottom: 0px;
-        left: 0px;
-        right: 140px;
+        top: 300px;
+        bottom: 500px;
+        left: 140px;
+        right: 540px;
         overflow: hidden;
     }
     .contents {
@@ -48,6 +43,8 @@
     {
         test = document.getElementById("test");
         addChildren(test);
+
+        document.body.offsetTop;
     }
     window.onload = runTest;
 </script>
@@ -56,4 +53,4 @@
     <div id="test"></div>
 </div>
 </div>
-crbug.com/426166: Tests positioned movement layout when it needs to layout children because it's width has changed.
+Tests positioned movement layout when its height has changed.