qemu.tests.qemu_guest_agent: Add windows guest support

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
qemu.tests.qemu_guest_agent: Update test steps for reboot test

This patch adds one more login step for qemu guest agent
reboot testing, to verify if the guest works well after
reboot.

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
qemu.tests.qemu_guest_agent: Log the exception when destroying vm

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
qemu.tests.cfg: Add windows guest support for qemu guest agent test

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
virt.cfg: Add config for windows suspend test of qemu guest agent

Signed-off-by: Qingtang Zhou <qzhou@redhat.com>