CI: Add ZTS -O option, log Setup Testing Machines step

Add a -O option to zfs-test.sh to dump debug information on test
timeout. The debug info includes:

• 30 lines from 'top'
• /proc/<PID>/stack output of process with highest CPU usage
• Last lines strace-ing process with highest CPU usage
• /proc/sysrq-trigger kernel stack traces

All debug information gets dumped to /dev/kmsg (Linux only).

In addition, print out the VM console lines from the "Setup Testing
Machines" step. We have often see VMs timeout at this step and don't
know why.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #17753