Two stars. PG-13. 129 minutes. It’s great to have a job watching — and then writing about — movies. But why does “Pirates of the Caribbean: Dead Men Tell No Tales” have to feel so much like work? To be sure, it’s always been something of an effort to keep track of who’s alive or dead or undead in this multi-sequel epic featuring walking pirate ghosts and characters who get killed off in one installment, only to be magically resurrected in the next — especially after what feels like eight long movies. What do you mean, this is only the fifth one?