What even are you, Last Witch Hunter? The ominous title and gothic poster suggest a grim action-fantasy flick – think Vin Diesel’s antihero Riddick shtick, but with witches – but we’re actually granted a slipshod, poorly-paced disappointment. Vin Diesel – sorry, “Kaulder” – was cursed with immortality some eight centuries ago, but where ‘curse’ would…