Since the indirect function table at index 0 in an instance is now
represented like the other tables, the IndirectFunctionTableEntry
abstraction is no more useful. We replace it with direct access to the
tables and a simpler abstraction {FunctionTargetAndRef}.

Bug: v8:11510
Change-Id: Iab4a6ca7eda8eb1757dbd321cb3997e98e78267e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3247030
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77754}