zfs-tests: verify zfs(8) and zpool(8) help message is under 80 columns
This commit updates the ZFS Test Suite to detect incorrect wrapping of
both zfs(8) and zpool(8) help message
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #8785