ftests: Add a test for cgroup_add_all_controllers()

ftests: Add a test for cgroup_add_all_controllers()

Add a test for cgroup_add_all_controllers()

-----------------------------------------------------------------
Test Results:
        Run Date:                          Mar 03 19:24:58
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
-----------------------------------------------------------------
Timing Results:
        Test                                             Time (sec)
        -----------------------------------------------------------
        setup                                                  0.00
        073-pybindings-cgroup_add_all_controllers-v2.py        0.08
        teardown                                               0.00
        -----------------------------------------------------------
        Total Run Time                                         0.08

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>