This makes sure that functions constructed via {WebAssembly.Function}
can be properly stored in globals of type "funcref". For now it is not
possible to call functions in such globals, but values can be loaded and
stored.

R=ahaas@chromium.org
TEST=mjsunit/wasm/type-reflection-with-anyref
BUG=v8:7742

Change-Id: I88ad1b5a57fd50e28723430803c528e674a94321
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1876815Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64539}