Kareem Abdul-Jabbar said goodbye to his long time friend Bill Walton after the basketball legend’s death Monday. The two shared their love of UCLA basketball and were fierce rivals on the NBA court. Two legends battling it out was quite the sight for basketball fans. The Hall of Famer wrote a thoughtful tribute to Walton after his passing. “My very close friend, fellow Bruin, and NBA rival Bill Walton died today,” Abdul-Jabbar wrote on Twitter. “And the world feels so much heavier now. On the court, Bill was a fierce player, but off the court he wasn’t happy unless he did everything he could t…