add timeout test case

tcp timeout init (SYN / SYNACK)
    tcp timeout handshake
    tcp timeout data
    tcp timeout half closed (session opening / session active)
    tcp timeout time wait
    udp timeout data (session opening / session active)

src/session/session_timer.cpp

@@ -68,7 +68,6 @@ struct session *session_timer_expire_session(struct session_timer *timer, uint64
     return sess;
 }
 
-// return interval to next required update, return 0 if no timer
 uint64_t session_timer_next_expire_interval(struct session_timer *timer)
 {
     return timeouts_timeout(timer->timeouts);