virttest.utils_misc: Add KSMController class.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
virttest.test_setup: Adjustments for utils_misc.KSMController.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
tests: Add test module for ksm services.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>