This adds support for loading and storing mutable imported globals
having a reference type in the interpreter. It expands existing test
coverage to the interpreter.

R=clemensh@chromium.org
TEST=mjsunit/wasm/anyref-globals-interpreter
BUG=v8:8091,v8:7581

Change-Id: I78e0c5c73664a183e1d92ec91eadf8b9a93e4787
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1559743Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60701}