DALLAS — Jamal Murray has a tendency to make situations more difficult on himself. When he slithers around a ball screen from Nikola Jokic or isolates in open space, his instinct and his dribble often compel him inside the 3-point arc, where contested jump shots are considered equally challenging but less valuable. When he was a rising prospect in high school, “at first he would make 100 free throws every day,” his former coach Larry Blunt recalled.