Add copy-within.js benchmark to resources in JSTests.json

This CL fixes the copy-within JSTest benchmark so it works on Android.

R=machenbach@chromium.org

Change-Id: I63662f9ab00d0199614681a53118bc4079e697ff
Reviewed-on: https://chromium-review.googlesource.com/1168488Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#55001}

test/js-perf-test/JSTests.json

@@ -659,9 +659,9 @@
       "path": ["Array"],
       "main": "run.js",
       "resources": [
-        "filter.js", "map.js", "every.js", "join.js", "some.js",
-        "reduce.js", "reduce-right.js", "to-string.js", "find.js",
-        "find-index.js", "from.js", "of.js", "for-each.js", "slice.js"
+        "filter.js", "map.js", "every.js", "join.js", "some.js", "reduce.js",
+        "reduce-right.js", "to-string.js", "find.js", "find-index.js",
+        "from.js", "of.js", "for-each.js", "slice.js", "copy-within.js"
       ],
       "flags": [
         "--allow-natives-syntax"