A SPOILER WARNING lurks below... tread carefully, dear readers! Run Sweetheart Run is what I'd tell you to do if I saw you standing in line for the latest Blumhouse movie, which hails from writer-director Shana Feste (Country Strong). Feste wastes an intriguing setup -- a woman tries to get home alive after her blind date turns violent -- on a terrible chase movie, replete with questionable performances, a stale synth score, and a cheesy ending boasting cheap visual effects. It reminded me of Blumhouse's last movie, Black Christmas, in that it's a complete head-scratcher. I always …