General Motors (NYSE: GM) said it has built 130 Chevrolet Bolt electric vehicles equipped with what it's calling its "next-generation" self-driving system, and it has begun testing them on public roads. In a milestone of sorts for the auto industry, these latest self-driving Bolts are the first autonomous vehicles ever to be built in a regular mass-production auto factory.In a step toward the mass-produciotn of self-driving cars, GM's latest batch of 130 Chevrolet Bolt autonomous test vehicles was built at GM's Orion Assembly Plant.