Ben Stiller gets extremely honest about his own shortcomings in a new documentary he produced about his parents, the late Jerry Stiller and Anne Meara. In the forthcoming doc, “Stiller & Meara: Nothing Is Lost,” the “Severance” director speaks to his daughter, 23-year-old Ella, about a project they worked on when she was young ― and why it led to one of his most profound mistakes. “I cut you out of ‘Secret Life of Walter Mitty,’” Ben Stiller says in conversation with Ella Stiller, referencing a