I don't believe this because whilst there are costs for the state of allowing self-driving cars, there are also massive upsides. The CompSci jobs that are involved in self-driving cars are highly sought after and by enticing testing of these cars Arizona is also likely bringing in high value tech jobs that would normally go to somewhere like silicon valley. Once they've established a center of excellence for that skill set it becomes self sustaining too. So you'll probably find that years after every state has self-driving cars Arizona still have more of those jobs.
For testing self driving cars on real streets though there's not really a big need for local developers if the company is setup well at all it can do it 99% remotely with just a barebones support staff onsite for installing the new software and sorting out integration issues which can also be done at their headquarters on engineering samples on their test tracks.
