When receiver is null or undefined we should not look into key. Calling
ToName on key is observable. This cl fixes the GenericKeyedLoadIC to
miss into runtime when the receiver is null or undefined.

Bug: v8:8394
Change-Id: Iaed07cd1b77b63e550284108777e165141af57a0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1605948Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61481}