ktest.pl: Fix missing "end_monitor" when machine check fails

stable inclusion
from stable-v5.10.173
commit 39255e4788fb5a27dd6957540a62b037aa7841ea
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BFR3

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=39255e4788fb5a27dd6957540a62b037aa7841ea



--------------------------------

commit e8bf9b98 upstream.

In the "reboot" command, it does a check of the machine to see if it is
still alive with a simple "ssh echo" command. If it fails, it will assume
that a normal "ssh reboot" is not possible and force a power cycle.

In this case, the "start_monitor" is executed, but the "end_monitor" is
not, and this causes the screen will not be given back to the console. That
is, after the test, a "reset" command needs to be performed, as "echo" is
turned off.

Cc: stable@vger.kernel.org
Fixes: 6474ace9 ("ktest.pl: Powercycle the box on reboot if no connection can be made")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>