“All I wanna do is cut hair, and they keep dropping.” A24 has a knack for finding a lot of strange and weird films, and the new film, “Medusa Deluxe,” definitely fits that bill. A British murder mystery set in a competitive hairdressing contest, the film is the feature-length directorial debut of Thomas Hardiman, known for shorts like “Pitch Black Panacea” (2020) and “Time on My Hands” (2012).