We add br.on_null, ref.as_non_null and ref.eq to the fuzzed module.
They are called when liftoff is used. ref.is_null has been changed,
according to comments from the last CL. GetRefType has been removed.

Bug: v8:11954
Change-Id: If93f6e9911cbcd3001ab45da02ebc037af8bdc54
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3122171
Commit-Queue: Rakhim Khismet <khismet@google.com>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76531}