[1936 Ja. 9, 17:2]   M'GROARTY'S COAT STOLEN 'There's a Robber In House—Or Maybe Senate,' Californian Shouts.     WASHINGTON, Jan. 8 (AP).—A charge that "there's a robber in the House" was made today by Representative McGroarty, Democrat of California, who quickly added, "or maybe in the Senate."    The Californian had turned from a speech championing the Townsend old age pension plan to announce that his [vicuña] overcoat, a gift from his wife, was missing.     "Although I was never intended to wear a $100 overcoat, I'd like to have it back," Mr. McGroarty appealed.