check_session.c: added test cases for multiple INVITEs and INVITE glare
check_session.c: added test cases for multiple INVITEs and INVITE glare

darcs-hash:20080910161057-db55f-de98254a6b107c5e3d61fb5119fd941c17a505eb.gz

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