As per the latest wasm-gc spec, all immediate arguments are removed
from ref.cast and ref.test.

Bug: v8:7748
Change-Id: I5839103276c4c5d51f3fa82a21cf2447cbb8ecaa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2649261
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72405}