- Do not create a new handle for {target_instance}.
- Only instantiate FunctionTargetAndRef once.

Bug: chromium:1284557
Change-Id: I42aea5750e93ef4ac578003bca323cda4753b6f6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3395874Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78686}