Rumors have been swirling for months Meryl Streep and Martin Short are more than just friends after bonding over traumatic moments in their love lives. And now RadarOnline.com can reveal the Only Murders in the Building costars are indeed smitten with each other. After filming a steamy scene for the upcoming fourth season of the Hulu hit, the senior screen icons were photographed laughing and holding hands both on the red carpet and at the afterparty for the show’s premiere on Aug. 22. An insider said: “It really is a case of life imitating art in the best way.” The source also claimed the PDA…