This is easily solvable. Manufacturers will take out umbrella liability policies to immunize them from lawsuits relating to self-driving failures. In order to price these policies, insurers will perform their own due diligence of the self-driving packages. The armies of lawyers employed by the auto makers will develop a boilerplate legal defense that will make massive lawsuits impractical, and most victims will settle out of court.
Alternately, your own auto liability insurance will include coverage for your car’s automaton, and again it will be priced based on risk. For most people, the premium will be lower than if they drive themselves, as the risk will be lower.