Use Parrot_pcc_invoke_sub_from_c_args instead of run_subs.:immediate
Use Parrot_pcc_invoke_sub_from_c_args instead of run_subs.:immediate

:immediate subs are expected to return a value ->P. :load, :init, and :postcomp do not (->). We don't need to save/restore the runcore, because PCC does that
We don't need to set the current constants segment in most places, because Sub.invoke does that

parrot/parrot,gitster/parrot,tkob/parrot,tkob/parrot,tkob/parrot,gagern/parrot,FROGGS/parrot,youprofit/parrot,youprofit/parrot,gitster/parrot,FROGGS/parrot,parrot/parrot,gagern/parrot,youprofit/parrot,FROGGS/parrot,gagern/parrot,parrot/parrot,parrot/parrot,tkob/parrot,gitster/parrot,gitster/parrot,youprofit/parrot,gagern/parrot,FROGGS/parrot,gagern/parrot,gitster/parrot,gagern/parrot,youprofit/parrot,tkob/parrot,gitster/parrot,gitster/parrot,tkob/parrot,youprofit/parrot,youprofit/parrot,FROGGS/parrot,tkob/parrot,FROGGS/parrot,FROGGS/parrot,FROGGS/parrot,gagern/parrot,tkob/parrot,parrot/parrot,youprofit/parrot