Changes

ttcn3-bts-test: do not start osmo-bts-virtual / virtphy containers

We cannot execute the virtphy based testcases due to the limitations
of Docker (see https://github.com/moby/libnetwork/issues/2397).  The
function starting the testsuite was already commented out, but not
the lines starting containers with osmo-bts-virtual and virtphy.

To put it simple, we start and immediately terminate those containers.
And since recently (Feb 1st), we started seeing socket creation errors
in both containers, causing jenkins.sh to abort early.  It's yet
unclear what's the cause of those socket errors, but regardless of
that we should still be running other pending testcases.

Change-Id: I7c9ccc9cc400edb7a05e222e51671fd49631a4cd
Fixes: OS#6352