The intrinsic default proto was not installed on async
function constructor, so the proto for those unable to
get a proper receiver fallbacks to the realms'
%Object.prototype%.

Bug: v8:9818
Change-Id: I08b9459d60da72dc894b983973e0a36019be9141
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3043691Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75866}