Jon Favreau is finally admitting he was wrong to warn Joe and Anthony Russo against killing off Tony Stark/Iron Man in 2019’s “ Avengers: Endgame .” Favreau gave rise to the Marvel Cinematic Universe when he cast Robert Downey Jr. as Iron Man in the 2008 movie of the same name. They re-teamed for 2010’s “Iron Man 2,” with Favreau continuing to work with Downey in other Marvel movies by playing Tony’s assistant and driver Happy Hogan. “I called the Russos. I was like, ‘I don’t know about — I don’