I don't think they kick you out. I don't have personal experience but from reading these boards you can be in the park eating and shopping but you cant go on the rides. They might not let you in after 7pm if that's when the park closes but if you are there already and have a dinner reservation I don't think they will kick you out (whether they actually do that). I would just make sure you are at the park way before 7pm.
Tonys is also right at the front entrance and if they did start ushering people out it would be on the way out anyway (on your left) as you are walking out. There's no need to check in that early then for a 7:20 adr.