test_sdp_termination()

struct gsm_mncc:
empty SDP: len=1896 sdplen=1046 sdp="\0" rc=0
empty SDP, shortest possible: len=851 sdplen=1 sdp="\0" rc=0
empty SDP, zero len: len=850 sdplen=0 sdp=- rc=-22
terminated SDP str: len=1896 sdplen=1046 sdp="Privacy is a desirable marketing option\0" rc=0
terminated SDP str, shortest possible: len=890 sdplen=40 sdp="Privacy is a desirable marketing option\0" rc=0
terminated SDP str, but len excludes nul: len=889 sdplen=39 sdp="Privacy is a desirable marketing option" rc=-22
terminated SDP str, but len too short: len=873 sdplen=23 sdp="Privacy is a desirable " rc=-22
len way too short: len=10 sdplen=-840 sdp=- rc=-22
len zero: len=0 sdplen=-850 sdp=- rc=-22

struct gsm_mncc_rtp:
empty SDP: len=1168 sdplen=1024 sdp="\0" rc=0
empty SDP, shortest possible: len=145 sdplen=1 sdp="\0" rc=0
empty SDP, zero len: len=144 sdplen=0 sdp=- rc=-22
terminated SDP str: len=1168 sdplen=1024 sdp="Privacy is a desirable marketing option\0" rc=0
terminated SDP str, shortest possible: len=184 sdplen=40 sdp="Privacy is a desirable marketing option\0" rc=0
terminated SDP str, but len excludes nul: len=183 sdplen=39 sdp="Privacy is a desirable marketing option" rc=-22
terminated SDP str, but len too short: len=167 sdplen=23 sdp="Privacy is a desirable " rc=-22
len way too short: len=10 sdplen=-134 sdp=- rc=-22
len zero: len=0 sdplen=-144 sdp=- rc=-22
