If a test requires Galera but it is not available, it is now skipped. All
tests that explicitly use the `test.galera` member as well as all tests
that use a Galera configuration now require that Galera is present.
Now the test program will
1) Write to each node in a Galera cluster and verify that the data
ends up in the slave.
2) At the end of 1) execute STOP SLAVE and START SLAVE to check that
replication can be stopped and started again (won't work unless
each node has the same server_id and value for @@log_bin_basename).
3) Block the node BLR is replicating from and expect it to connect
to the next configured master and that replication continues to
work. Do that for all nodes.
4) Stop MaxScale and restart it and expect 3) to work. That checks
that BLR saves all necessary information in master.ini and is
capable of reading it.
It should be possible to START SLAVE and STOP SLAVE irrespective
of which Galera node updates are mode to.
That will be the case if @@log_slave_updates is on and each node
in the Galera cluster have the same server id. Otherwise it will
fail with the current incarnation of BLR.
