Following defendant's conviction for committing first-degree murder when he was a juvenile, defendant was mandatorily sentenced to life imprisonment without parole; after U.S. Supreme Court held in Miller v. Alabama that sentences such as defendant's are unconstitutional, the trial court held a resentencing hearing and imposed another sentence of life without parole; whether the resentencing statutes enacted in response to Miller (N.C.G.S. 15A-1340.19A to -1340.19D) are unconstitutional.