Of all the good, bad and questionable moments last night on “SNL40,” my favorite was Miley Cyrus. This girl can saing. She could give up all the affectations, the shock photo shoots, and all the rest. She has the makings of a great singer, not just a good one. She can stop taking a wrecking ball to everything in her path, and just cool out now. Her rendition of Paul Simon’s “50 Ways to Leave Your Lover” could signal a new path for her, just as Lady Gaga has settled into “real” singing with Tony Bennett.