The Dallas Mavericks lost their second consecutive game in blowout fashion against the Boston Celtics on Wednesday night. Luka Doncic did his part, as he normally does, but his supporting cast let him down once again. The Dallas Mavericks hoped to start off a tough, three-game road trip before Thanksgiving by bouncing back into the win column against the Eastern Conference-leading Boston Celtics at TD Garden on Wednesday. The Celtics, who had fallen victim to Luka Doncic and Spencer Dinwiddie game-winning shots the last three times they had played the Mavs, had other plans, as they rode a hot-shooting first…