selftest/cgroup: Update test_cpuset_prs.sh to match changes

Unlike the list of isolated CPUs, it is not easy to programamatically
determine what sched domains are being created by the scheduler just
by examinng the data in various kernfs filesystems. The easiest way
to get this information is by enabling /sys/kernel/debug/sched/verbose
file to make those information displayed in the console. This is also
what the test_cpuset_prs.sh script is doing when the -v flag is given.

It is rather hard to fetch the data from the console and compare it to
the expected result. An easier way is to dump the expected sched-domain
information out to the console so that they can be visually compared
with the actual sched domain data. However, this have to be done manually
by visual inspection and so will only be done once in a while.

Moreover the preceding cpuset commits also change the cpuset behavior
requiring corresponding chanages in some test cases as well as new test
cases to test the newly added functionality.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>