ftests: Add cgset invalid options test

ftests: Add cgset invalid options test

Add a test that tests various invalid flag combinations to cgset.

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Test Results:
        Run Date:                          Mar 08 17:39:20
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
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Timing Results:
        Test                                    Time (sec)
        ---------------------------------------------------------
        setup                                        18.15
        027-cgset-invalid_options.py                  0.94
        teardown                                      0.00
        ---------------------------------------------------------
        Total Run Time                               19.09

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>