With MDEV-12288 and MDEV-13536, the InnoDB purge threads will access
pages more often, causing all sorts of debug assertion failures in
the B-tree code.

Work around this problem by amending the corruption tests with
--innodb-purge-rseg-truncate-frequency=1 --skip-innodb-fast-shutdown
so that everything will be purged before the server
is restarted to deal with the corruption.