shed more than a few tears leading up to the final episode of her eponymous talk show.But her last dance on Thursday, May 26, will be an especially “emotional” one, an insider who was at the taping has told The Post.In her remaining weeks after nearly two decades on air, she’s welcomed some final face time with a procession of A-list guests including Oprah Winfrey, Justin Timberlake, just-anointed “Saturday Night Live” alum Kate McKinnon, Michelle Obama, Sean “Diddy” Combs, potty-mouthed Julia Louis-Dreyfus, Kevin Hart, Chelsea Handler and Michael B. Jordan, among others.But the show source said her tears have been “happy” ones untinged by bitterness or regret, despite the heavy cloud hanging over her since allegations of a “toxic” work environment first cast a pall over her “be kind” brand.