I could be wrong but i think that Patrol is an inherent part of the 'Amov' ability :/
So it wouldn't be possible.
In the past i've already scan to find all "hidden" unit abilities in game, simply by increasing an integer from 0 and using GetUnitAbilityLevel in a big loop and a short periodic timer, i'm quite sure (but not 100 %) that there was only 'Amov', i mean obviously you have the attack 'Aatk' ability and so one, but nothing related to patrol.