ttcn3-sgsn-test: add missing SGSN_Tests_NS.control
This does not enable the SNS testcases though. We need a separate
job with its own configuration files for running the SNS testcases.
Change-Id: I605526dff6d3c0ec4c5dc58dc00ca51b4ccd68a7
Related: osmo-ttcn3-hacks.git Ib2bffbb110961474928f35d212cb492d4b6fdee0
