qemu.tests: new test monitor_cmds_check

Check some advance commands not include qemu-kvm package

changes from v1:
    1. instead private code with function in framework
    2. fixed typo
    3. calll monitor.verify_supported_cmds driectly to check commands
    unavaliable
changes from v2:
    1. add notes in docstring
    2. instead filter function

Signed-off-by: Xu Tian <xutian@redhat.com>