This will send a static message. It will trigger the GMM code
on the SGSN and might ask us for the IMEI/IMSI or send us an
accept. As we are not replying at all the SGSN needs to send new
requests and we can observe if the sequence number is increasing
like it should.
As a last minute change I probably ran git rebase --whitespace=fix
on the patch set and broke the test result. Update the expected
file and tests should pass.