This adds new tests to verify pmksa_cache_preauth when
used with per_sta_vif and possibly vlans.
While at it it refactors the code such that the tests
pmksa_cache_preauth
pmksa_cache_preauth_vlan_enabled
pmksa_cache_preauth_vlan_used
pmksa_cache_preauth_per_sta_vif
pmksa_cache_preauth_vlan_enabled_per_sta_vif
pmksa_cache_preauth_vlan_used_per_sta_vif
share code where possible.
Signed-off-by: Michael Braun <michael-dev@fami-braun.de>