s2tcase.c: use new _tcase_add_test() API.
s2tcase.c: use new _tcase_add_test() API.

unispeech/sofia-sip,xhook/sofia-sip,jart/sofia-sip,unispeech/sofia-sip,xhook/sofia-sip,BelledonneCommunications/sofia-sip,BelledonneCommunications/sofia-sip,erdincay/sofia-sip,erdincay/sofia-sip,BelledonneCommunications/sofia-sip,xhook/sofia-sip,BelledonneCommunications/sofia-sip,erdincay/sofia-sip,jart/sofia-sip,xhook/sofia-sip,xhook/sofia-sip,unispeech/sofia-sip,unispeech/sofia-sip,jart/sofia-sip,erdincay/sofia-sip