add sctp_default_prinfo for [gs]etsockopt syscall

gtests/net/packetdrill/lexer.l

gtests/net/packetdrill/parser.y

gtests/net/packetdrill/run_system_call.c

gtests/net/packetdrill/script.c

gtests/net/packetdrill/script.h

gtests/net/packetdrill/symbols_freebsd.c

...et/packetdrill/tests/bsd/sctp/sctp_get_socket_options.pkt