By Tom Hals WILMINGTON, Del (Reuters) – Billionaire Elon Musk’s tendency to dish out insults while being questioned under oath will be tested anew on Monday, when lawyers for Twitter Inc are due to interview the Tesla Inc CEO about his abrupt decision in July to ditch his $44 billion deal for the social media company. Testifying in past legal battles, the world’s richest person has called opposing attorneys “reprehensible,” questioned their happiness and accused them of “extortion.” He asked one attorney if he was working on a contingency because the lawyer’s client was allegedly behind on chi…