benchmark/index.js: Use radix in |parseInt| call

Fixes the following JSHint error:

  ./benchmark/index.js: line 59, col 18, Missing radix parameter.

benchmark/index.js

@@ -56,7 +56,7 @@ $("#run").click(function() {
    *   2. To minimize random errors.
    */
 
-  var runCount = parseInt($("#run-count").val());
+  var runCount = parseInt($("#run-count").val(), 10);
   if (isNaN(runCount) || runCount <= 0) {
     alert("Number of runs must be a positive integer.");
     return;