Joe Biden vowed Friday to stay in the White House race and blamedhis dismal debate performance on “feeling terrible” due to a cold, as he sought to save his reelection campaign with a make-or-break TV interview. As rebellion brews among some nervous Democratic voters, lawmakers and donors, the one-to-one with the ABC network was hyped as the most consequential of the 81-year-old’s long career. “I was sick, I was feeling terrible… We were trying to figure out what’s wrong,” the president said in an excerpt of his first TV interview since the debate with Donald Trump. “They did a test to see w…