The sicko who smashed his own feces in a Bronx straphanger’s face joked with cops that “s–t happens” before sneering to a Bronx judge, “F–k you, bitch.” Frank Abrokwa, 37, was busted Monday at his homeless shelter in connection to the Feb. 21 attack. Upon arrest, he made light of the attack, quipping to cops, “S–t happens. Haha. This is a s–tty situation. Haha,” Bronx Assistant District Attorney Grace Phillips said during Abrokwa’s arraignment late Tuesday. Abrokwa — apparently impatient because Brooklyn detectives showed up to arrest him for an unrelated hate crime from September — also made a scene...