detect VTY TELNET port connection failures in TTCN3 tests

Pass the CTRL_DETECT_CONNECTION_ESTABLISHMENT_RESULT parameter to
the TELNET port by default. This allows tests to make progress
into an error handling path if they are started while the osmo-*
program they want to connect on VTY is not running.

Observed with osmo-ggsn tests, where if the one test runs
into a VTY connection failure the subsequent test would get
stuck forever in a map() call on the VTY TELNET port.

Change-Id: I9acf7793d5d68aec6d087cff254a10d8b673dab1
Related: OS#3149
8 files changed