Gov. Charlie Baker offered an impassioned defense of his legislation aimed at tackling the state’s opioid crisis yesterday, saying the deaths must stop.“I don’t want to be the governor who ends up presiding over 2,500 opioid deaths, or 3,000 in one year … or 3,500. Especially when there are things that can be done to deal with this,” Baker told the several hundred in attendance at the New England Council Opioid Abuse Forum at the Seaport Hotel.