So I noticed that Zombie Villagers now have clothing. Each corresponding to the clothes of Actual Villagers. So I tested this out and curing a Zombie Villager with a specific clothing on ( for example white clothing ) it would have to turn into a librarian, but that's not what happens its the still the same curing mechanics as back in 1.8 or a snapshot before this one, so the Villager will be random. If this is not a bug then this would make no sense to add clothes on Zombie Villagers.