Add test for virt-top and virt-xml-validate. (qemu & lxc)

unused variable, perhaps you want to use it like `id_result = virsh.domid(vm_name, uri=connect_uri)`. I suggest 
`id_result = vm.get_id()` way because get_id() was defined to be `return virsh.domid(self.name, uri=self.connect_uri).stdout.strip()`, the `connect_uri` can be removed.