When news broke earlier this month that Warner Bros. would be shelving the nearly complete “Batgirl” instead of releasing it as planned on HBO Max, it prompted an immediate question: What would become of “The Flash”? While both DC superhero films were highly anticipated, the future of the latter seemed more questionable at times given that it stars Ezra Miller, the 29-year-old actor who has faced multiple criminal charges — in addition to abuse and assault allegations — over the past several months.