Fix calling of functions whose parameters are of an implicitly declared datatype (currently only makes sense for REF_TO datatypes, but may make sense to other datatypes too if the datatype model is changed in the future).

STD_TEST.st
STD_RESSOURCE.c
LOCATED_VARIABLES.h
POUS.c
test
STD_CONF.c
SFC_TEST.st
test.exe
plc.st
POUS.h
VARIABLES.csv