[class] add initialize-instance.js to JSTests3 resources

Bug: v8:12432
Change-Id: Ib082a390f7f71cc5e5bc4cdeb2a90596d9c16638
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3302283Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/main@{#78090}

test/js-perf-test/JSTests3.json

@@ -14,7 +14,7 @@
       "name": "ClassFields",
       "path": ["ClassFields"],
       "flags": ["--allow-natives-syntax"],
-      "resources": [ "evaluate-class.js", "classes.js" ],
+      "resources": [ "evaluate-class.js", "initialize-instance.js", "classes.js" ],
       "tests": [
         {
           "name": "EvaluateClassOpt",