Bug 1618202 - Mark the previously annotated test as random as it fails in opt but passes in debug (o.O)

MANUAL PUSH: Trying to get the android stuff to stick once again CLOSED TREE.

layout/reftests/forms/input/range/reftest.list

@@ -21,7 +21,7 @@ fuzzy-if(skiaContent,0-1,0-40) == stepDown-unthemed.html 75pct-unthemed-common-r
 == stepDown.html 75pct-common-ref.html
 fuzzy-if(skiaContent,0-1,0-40) == stepUp-unthemed.html 75pct-unthemed-common-ref.html
 == stepUp.html 75pct-common-ref.html
-fails-if(!nativeThemePref) == max-prop.html 100pct-common-ref.html # Snapping, bug 1621141
+random-if(!nativeThemePref) == max-prop.html 100pct-common-ref.html # Snapping in different ways in debug and opt builds, bug 1621141
 == reset-value.html reset-value-ref.html
 
 # 'direction' property: