A judge chillingly foresaw David Mazariegos’ escalating violence as he begrudgingly lowered his bail in an assault case — just months before the maniac allegedly beat a beloved security guard to death outside a Brooklyn subway station. The premonition by Manhattan Judge Robert Rosenthal was revealed in a transcript from a July hearing, after prosecutors couldn’t secure a felony assault charge against Mazariegos, 25, in a case with eerie echoes to his later alleged fatal beating of Nicola Tanzi,