Initial TTCN-3 test suite for osmo-remsim

This adds shared infrastructure and initial test suites for
osmo-remsim-{server,client,bankd}.

Change-Id: I00034d3a991f0f881cfd8ff0bfc4557113daf830
diff --git a/Makefile b/Makefile
index 2c8e951..99243d6 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-SUBDIRS=bsc bsc-nat bts ggsn_tests hlr mgw msc pcu sccp selftest sgsn sip sysinfo
+SUBDIRS=bsc bsc-nat bts ggsn_tests hlr mgw msc pcu remsim sccp selftest sgsn sip sysinfo
 
 NPROC=$(shell nproc 2>/dev/null)
 ifeq ($(NPROC),)