Convenience store stocks are having their moment, riding a wave of investor demand for more defensive plays as angst over the sustainability of the artificial intelligence boom and the ongoing conflict in Iran drive increased market turbulence.Shares of the group’s biggest names — Alimentation Couche-Tard Inc., Casey’s General Stores Inc., and Murphy USA Inc. — have surged to near record levels and are all up at least 24% this year. The leader of the pack, Casey’s, is up more than 54% and on track for its b ...