A prototype for a redesigned Audi A4 has been spotted again. The prototype is for the A4 Avant wagon body style, but testers for the sedan should be out and about shortly. While Audi doesn’t offer the A4 Avant in the U.S., we still get the wagon body in A4 Allroad soft-roader guise. The current A4, the B9, arrived for the 2017 model year and was…