recursive types: fix implementation of references_name (#50963)
To do the old version correctly, we would need to carefully track
whether we end up using that parameter as a parameter of any apply_type
call in the fieldtype computation of any of the fields, recursively.
Since any of those might cause recursion in the constructor graph,
resulting in trying to layout some concrete type before we have finished
computing the rest of the fieldtypes. That seems unnecessarily difficult
to do well, so instead we go back to just doing the trivial cases.
