Fix groups issue in tests using perm_app_set_privilege api.

Fix groups issue in tests using perm_app_set_privilege api.

Due to current policy process calling perm_app_set_privilege is added
to current groups of app user and additional groups associated with
smack label in database. Previous tests did not take into account
current groups of app user.

Verification:
-> security-tests.sh libprivilege-control --runignored --output=text

Change-Id: I03a7e96c46da20af6a01c86b290fc7180425afb5