VMState test: query command to extract the qdevified device names

Signed-off-by: Sanidhya Kashyap <sanidhya.iiith@gmail.com>
VMstate test: basic VMState testing mechanism

Signed-off-by: Sanidhya Kashyap <sanidhya.iiith@gmail.com>
VMState test: querying the vmstate testing process

Signed-off-by: Sanidhya Kashyap <sanidhya.iiith@gmail.com>
VMState test: update period of vmstate testing process

Signed-off-by: Sanidhya Kashyap <sanidhya.iiith@gmail.com>
VMState test: cancel mechanism for an already running vmstate testing process

Signed-off-by: Sanidhya Kashyap <sanidhya.iiith@gmail.com>