[flang] Call finalization on empty type (#66010)

According to 7.5.6.3 point 3, finalization occurs when

> A nonpointer, nonallocatable object that is not a dummy argument or
function result is finalized immediately before it would become
undefined due to execution of a RETURN or END statement (19.6.6, item
(3)).

We were not calling the finalization on empty derived-type. There is no
such restriction so this patch updates the code so the finalization is
called for empty type as well.