Comcast’s third-quarter profits doubled to $4 billion, boosted by broadcast revenues from the Tokyo Olympics and more customers returning to theme parks during the pandemic. Revenues at the NBCUniversal unit rose nearly 58% to $10 billion, including $1.8 billion from the Summer Games. The Universal Studios Orlando theme park reported its most profitable quarter, helping the parks segment increase revenue from $1.1 billion to $1.4 billion. The Philadelphia media giant’s cable business saw revenues rise despite slower customer growth. The company netted 255,000 cable customers, way down from the…