Add support for the column-fill property.

LayoutTests/fast/multicol/progression-reverse-overflow.html

 <style>
     div.test {
         width: 100px;
         height: 100px;
         -webkit-column-width: 100px;
         -webkit-column-gap: 0;
         -webkit-column-progression: reverse;
+        column-width: 100px;
+        column-gap: 0;
+        column-fill: auto;
         overflow: hidden;
     }
 
     div.test > div {
         -webkit-logical-height: 100%;
     }
 
     div.test > div:first-child {
         background-color: red;
     }
@@ skipping 25 matching lines @@
     for (var i = 0; i < tests.length; ++i) {
         var test = tests[i];
         if (test.scrollLeft)
             test.scrollLeft = 0;
         else
             test.scrollLeft = test.scrollWidth;
         if (test.scrollTop)
             test.scrollTop = 0;
     }
 </script>