Betty Buckley, the Tony-winning actress and singer best known for her rendition of “Memory” in “Cats,” secretly buried her dog, Rags the Yorkshire Terrier, in the garden of the Chateau Marmont years ago. “She is buried underneath what used to be the Marlboro Man big billboard on Sunset Boulevard,” Buckley tells author Jeryl Brunner in her book “My City, My Los Angeles,” out on Amazon now and shelves April 16. Buckley explains her brother, Norman, a TV director, advised against the sneaky burial — but Buckley went with a friend to complete the mission anyway. “We went out to the front, dug the grave . . . sang some hymns, and told Rags stories, and buried her there.”