ftests: Add test to delete cgroup on shared mount point

ftests: Add test to delete cgroup on shared mount point

The user might try to delete the cgroup created on a mount point shared
by cgroup v1 controllers, once for each controller.  This functional
test emulates the deletion behavior and expects the test to pass without
complaint about missing directory, when attempted to delete on the
second controller.

-----------------------------------------------------------------
Test Results:
        Run Date:                          Apr 23 06:44:27
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
-----------------------------------------------------------------
Timing Results:
        Test                                       Time (sec)
        -----------------------------------------------------
        setup                                            0.00
        047-cgcreate-delete_cgrp_shared_mnt.py           0.03
        teardown                                         0.00
        -----------------------------------------------------

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