selftest/cgroup: Add a remote partition transition test to test_cpuset_prs.sh

The current cgroup directory layout for running the partition state
transition tests is mainly suitable for testing local partitions as
well as with a mix of local and remote partitions. It is not that
suitable for doing extensive remote partition and nested remote/local
partition testing.

Add a new set of remote partition tests REMOTE_TEST_MATRIX with another
cgroup directory structure more tailored for remote partition testing
to provide better code coverage.

Also add a few new test cases as well as adjusting existig ones for
the original TEST_MATRIX.

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