Former President Barack Obama took aim at his successor, Donald Trump’s, economic record — and “hazy memory” — as he took the stage during Kamala Harris’ rally in Pittsburgh Thursday. “Donald Trump’s plan is to do what he did last time, which was give another massive tax cut to billionaires and big corporations,” Obama told the crowd. “And the reason some people think, ‘I don’t know, I remember that economy when [Trump] first came in being pretty good.’ Yeah, it was pretty good. Because it was my economy.” As Harris supporters cheered, the 44th president continued, “We had had 75 straight mont…