I'm not sure about GM and Test Track but I know Mission Space has an HP lounge. You show your badge and they lead you to a private lounge that overlooks the game area. There are soft drinks, water, coffee (all free), photo machines, wifi, comfy seating and a private restroom. They also use the area for Wish trips to get away from the crowds and relax. When you are ready, there is a backdoor entrance to the ride that cuts out most of the line.
I know there are several corporate sponsorships with private lounges, not sure how similar they all are.