Add test for dynamic cgroup subsystem settings.

Docker-DCO-1.1-Signed-off-by: Jialin Tian <himurakenshin54@gmail.com> (github: kenshin54)
Use gofmt to format code.

Docker-DCO-1.1-Signed-off-by: Jialin Tian <himurakenshin54@gmail.com> (github: kenshin54)