Portraying an overzealous Patriots fan opposite Tom Brady in a 2012 “Funny or Die” video was a career highlight for Quincy actor Mike Mitchell. But as coach Bill Belichick would say, he’s onto “Tomorrow.” Mitchell, a 2001 graduate of North Quincy High, co-stars with Chris Pratt in the alien-invasion thriller, “The Tomorrow War,” out July 2 on Amazon Prime. The two play time-traveling soldiers going 30 years into the future to erase a threat to all humanity. Brady might have helped Mitchell gain fame with the “Funny or Die” bit, but Pratt, the star of the blockbuster franchises “Jurassic World” and “Guardians of the Galaxy” is now Mitchell’s ride-or-die.