Add a test case for when the QEMU_CAPS_NO_KVM_PIT capability is set.
This capability is mutually exclusive to QEMU_CAPS_KVM_PIT_TICK_POLICY
and results in the same output regardless of whether "discard" or
"delay" was specified in the guest XML for 'tickpolicy'.
Signed-off-by: NMaxim Nestratov <mnestratov@virtuozzo.com>