MSC_Tests.ttcn: introduce TC_gsup_mt_multi_part_sms

The idea of this test case is to verify the process of multi-part
MT SMS transmission. The MSC should keep the RAN connection until
the last message part is transmitted.

Change-Id: I6308586a70c4fb3254c519330a61a9667372149f
Related: OS#3587
2 files changed