aarch64 do not support vcpu hot-unplug, remove it temporary.
Signed-off-by: NJie Tang <tangjie18@huawei.com>

Add some test cases to test vcpu device hot plug and unplug. And after
that, do some sub test, verify guest work well and the number of vcpu is
the same as expected.
Signed-off-by: NYihuang Yu <yihyu@redhat.com>