Add another regression test for LP: #1536662 and LP: #1541188.
This one ensures we haven't simply moved the hangs/crashes to some
later point in the Mir server's lifetime. Fixes: https://bugs.launchpad.net/bugs/1536662, https://bugs.launchpad.net/bugs/1541188.
Approved by mir-ci-bot, Cemil Azizoglu.