“Stag” arrives in the shadow of “The Hangover,” though this tale of bachelor party shenanigans emerges from the Canadian film industry. Just how Canadian is this movie? Well, there’s a stripper, but she remains clothed for 99% of her screentime and the feature ends with a father reaffirming his love for his family. “Stag” isn’t exactly a raunchy explosion of men behaving badly, and it’s not all that funny either. True to its Canadian heritage, it’s mild stuff, hoping to come across triumphantly ill-mannered with erection jokes and the occasional curse word, missing a devilish spark that could a...