Vince Vaughn and Mel Gibson, whose 2016 war film “Hacksaw Ridge” received six Oscar nominations, are reuniting for a gritty crime film about police brutality. In “Dragged Across Concrete,” directed by “Bone Tomahawk” filmmaker S. Craig Zahler, Mr. Vaughn and Mr. Gibson will play two policemen who get suspended after a video of their strong-arm tactics…