This CL removes the CallRefData data structure and accesses a funcref's
target and instance through the funcref.

Bug: v8:7748
Change-Id: Ic46b127f7775052d5df13b03c447e3b15328ad74
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3306486
Commit-Queue: Richard Stotz <rstz@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78194}