[builtins] Removing %_CallFunction in GetThirdIndex.

By using an InternArray for the pivot calculation we can get rid of yet
another %_CallFunction.

Review URL: https://codereview.chromium.org/1316673008

Cr-Commit-Position: refs/heads/master@{#30636}

src/array.js

@@ -915,15 +915,19 @@ function InnerArraySort(array, length, comparefn) {
   };
 
   var GetThirdIndex = function(a, from, to) {
-    var t_array = [];
+    var t_array = new InternalArray();
     // Use both 'from' and 'to' to determine the pivot candidates.
     var increment = 200 + ((to - from) & 15);
-    for (var i = from + 1, j = 0; i < to - 1; i += increment, j++) {
+    var j = 0;
+    from += 1;
+    to -= 1;
+    for (var i = from; i < to; i += increment) {
       t_array[j] = [i, a[i]];
+      j++;
     }
-    %_CallFunction(t_array, function(a, b) {
+    t_array.sort(function(a, b) {
       return comparefn(a[1], b[1]);
-    }, ArraySort);
+    });
     var third_index = t_array[t_array.length >> 1][0];
     return third_index;
   }