This implements __functor calling in situations where `OpTailCall` is
used, but not yet for `OpCall`.
For some reason I have not yet figured out, this same implementation
does not work in call_value, which means that it also doesn't yet work
in builtins that apply functions.
Change-Id: I378f9065ac53d4c05166a7d0151acb1f55c91579
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6826
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
