The mount directory for the selftests cgroup tree might
not exist so let's make sure it does exist by creating
it ourselves if it doesn't exist.
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-9-daan.j.demeyer@gmail.comSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>