Due to recent spec changes, We do not have to check if ref.func
instructions in global declarations only refer to declared functions.
Additionally functions referenced in exports and globals are now
considered declared.

R=ecmziegler@chromium.org

Bug: v8:10556
Change-Id: I79856c7d68155a04eb36769ceed8a58fe62a9f9f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2228653
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Emanuel Ziegler <ecmziegler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68190}