ZTS: Increase redundancy test timeout

The redundancy_draid.ksh and redundancy_raidz.ksh tests were updated
by commit 93c8e91fe to additionally verify self-healing. This
additional check increased the run time which can now occasionally
exceed the default maximum timeout in the CI environment. To prevent
this from causing failures increase the default timeout for the
redundancy test cases.

Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #12043