bsc: add MSC pooling tests

The MSC pooling feature is implemented in osmo-bsc
Ifbdea197b26e88751a391c8a80c41f04e7d5e047.

A VTY command ('mscpool roundrobin next') that allows deterministic testing is
added in I2155d906505a26744966f442ffb1e87a6a9b494c.

osmo-bsc.cfg changes needed for these tests to succeed are in docker-playground
I1986e4ef43beee161c82193694421b56136c1afe

The new tests will fail until the above have been merged.

Change-Id: I21cbab193cd0de2e5692665442eae113d5f61904
3 files changed