tests: Add pvpanic qtest

Signed-off-by: Andreas Färber <afaerber@suse.de>
qtest: Factor out qtest_qmp_receive()

Signed-off-by: Andreas Färber <afaerber@suse.de>
pvpanic-test: Assert pause event

Signed-off-by: Andreas Färber <afaerber@suse.de>
tests: Add i82801b11 qtest

Signed-off-by: Andreas Färber <afaerber@suse.de>