Elliott Gould helped care for Groucho Marx in the waning days of the Hollywood legend’s life. “I became friends with Groucho in his later days,” Gould revealed Saturday after a screening of his 1974 film “California Split.” “I used to shave his face with an electric razor. I once changed a light bulb over his bed, and he told me, ‘That’s the best performance I’ve ever seen you give.’ I said, ‘Well, that’s the best review I ever got.’ ” “Split” was part of Lincoln Center’s “Jew Wave” series, which included “Funny Girl,” starring Gould’s ex, Barbra Streisand.