add case for virtio-mem coldplug and cold unplug

[nanli1]

xxxx-299161:Virtio-mem memory device cold-plug and cold-unplug Signed-off-by: nanli [email protected]

x86+rhel9

avocado run --vt-type libvirt --test-runner=runner --vt-machine-type q35 memory.devices.virtio_mem.coldplug_and_unplug

 (1/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.with_addr: PASS (37.79 s)
 (2/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.source_and_mib: PASS (38.10 s)
 (3/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.unplug_none_dev: PASS (37.92 s)
 (4/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.plug_exceeded_max_mem: PASS (38.28 s)
 (5/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.duplicate_addr: PASS (37.97 s)

arm+rhel9(The last scenario has different result with x86, Feature owner confirmed it's a know issue )

avocado run --vt-type libvirt --test-runner=runner --vt-machine-type arm64-mmio memory.devices.virtio_mem.coldplug_and_unplug

 (1/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.with_addr: PASS (32.23 s)
 (2/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.source_and_mib: PASS (33.34 s)
 (3/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.unplug_none_dev: PASS (33.16 s)
 (4/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.plug_exceeded_max_mem: PASS (32.74 s)
 (5/5) type_specific.io-github-autotest-libvirt.memory.devices.virtio_mem.coldplug_and_unplug.duplicate_addr: FAIL: Expect should fail but got: Device attached successfully\n\n\n (33.19 s)