Former President Donald Trump delivered one of his angriest post-trial day rants in Manhattan on Monday after his former attorney and fixer Michael Cohen — one of the most important witnesses for District Attorney Alvin Bragg — took the stand to testify about his own role in the alleged criminal scheme. The former president has made several such speeches at the end of trial arguments, often followed immediately by crushing fact-checks that strip away his false claims — but on Monday he lost his cool more than usual. “The whole is laughing now at New York’s weaponized legal system, watching thi…