[jstest] Fix ElementsKind of the array that gets sorted

This CL fixes the "sort-lengths" benchmark so the ElementsKind of the
array to sort is PACKED_SMI again. This was somehow broken.

R=jgruber@chromium.org

Change-Id: I129e001eae4c88e9f99174b3494193232d933c3f
Reviewed-on: https://chromium-review.googlesource.com/1188122Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#55371}

test/js-perf-test/ArraySort/sort-lengths.js

@@ -9,6 +9,7 @@ function SortAsc() {
 }
 
 function Random(length) {
+  array_to_sort = [];
   for (let i = 0; i < length; ++i) {
     array_to_sort.push(Math.floor(Math.random() * length));
   }
@@ -16,21 +17,16 @@ function Random(length) {
 }
 
 function Sorted(length) {
+  array_to_sort = [];
   for (let i = 0; i < length; ++i) {
     array_to_sort.push(i);
   }
   AssertPackedSmiElements();
 }
 
-function TearDown() {
-  array_to_sort = [];
-}
-
 function CreateSortSuitesForLength(length) {
-  createSortSuite(
-      'Random' + length, 1000, SortAsc, () => Random(length), TearDown);
-  createSortSuite(
-      'Sorted' + length, 1000, SortAsc, () => Sorted(length), TearDown);
+  createSortSuite('Random' + length, 1000, SortAsc, () => Random(length));
+  createSortSuite('Sorted' + length, 1000, SortAsc, () => Sorted(length));
 }
 
 CreateSortSuitesForLength(10);