Each of the three quarterbacks on the  San Diego State Aztecs ’ roster led scoring drives in a scrimmage Saturday that capped spring drills.  On the flip side, the defense came up with several big plays, including a stop on the goal line and an interception.  It was the 15th and final spring practice for the Aztecs, who are looking to build on last year’s 9-4 record as they move into the new-look Pac-12. Scrimmage action Returning starter Jayden Denegal led the No. 1 offense deep into the defensive territory on the third possession, thanks mostly to a 40-yard pass on fourth down to freshman Daishaun Davis. Denegal later ran for a first down and SDSU eventually got into the red zone. However, on fourth-and-goal from the 1, the offense was stuffed on the line of scrimmage. Draiden Trudeau entered on the fifth possession and led the No. 3 offense on a 13-play, 67-yard drive, capped by a 1-yard touchdown run by Christian Washington on fourth down.…