ctdb-test: Adding test case to verify queue resizeing

ctdb-test: Adding test case to verify queue resizeing

If a data packet arrives which exceeds the queue's current buffer size,
the buffer needs to be increased to hold the full packet. Once the packet
is processed the buffer size should be decreased to its standard size again.
This test case verifies this process.

Signed-off-by: Swen Schillig <swen@linux.ibm.com>
Reviewed-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Christof Schmitt <cs@samba.org>
Autobuild-User(master): Christof Schmitt <cs@samba.org>
Autobuild-Date(master): Wed Apr 10 00:17:37 UTC 2019 on sn-devel-144