Bug 1638107 - css-simple-styling.html is two pixels more wrong in WR.

MANUAL PUSH: Fixing orange in a CLOSED TREE

layout/reftests/css-placeholder/reftest.list

@@ -2,6 +2,6 @@ include input/reftest.list
 include textarea/reftest.list
 
 fuzzy-if(skiaContent,0-1,0-4) == css-restrictions.html css-restrictions-ref.html
-fuzzy-if(gtkWidget,255-255,1376-1496) == css-simple-styling.html css-simple-styling-ref.html # gtkWidget, Bug 1600749
+fuzzy-if(gtkWidget,255-255,1376-1498) == css-simple-styling.html css-simple-styling-ref.html # gtkWidget, Bug 1600749
 != css-background.html css-background-ref.html
 fuzzy-if(skiaContent,0-1,0-180) == ignore-pseudo-class.html ignore-pseudo-class-ref.html