Cleanup baseFill.

lodash.js

@@ -2403,7 +2403,7 @@
     function baseFill(array, value, start, end) {
       var length = array.length;
 
-      start = start == null ? 0 : toInteger(start);
+      start = toInteger(start);
       if (start < 0) {
         start = -start > length ? 0 : (length + start);
       }
@@ -2411,10 +2411,8 @@
       if (end < 0) {
         end += length;
       }
-      length = start > end ? 0 : (end >>> 0);
-      start >>>= 0;
-
-      while (start < length) {
+      end = start > end ? 0 : toLength(end);
+      while (start < end) {
         array[start++] = value;
       }
       return array;