Gov. Ned Lamont threatened Wednesday to clamp down on state borrowing if legislators can’t agree in special session this summer on a plan to toll Connecticut’s major highways. Lawmakers declined to adopt any long-term financing plan for transportation work during the regular session, which adjourned on June 5. But they must return to the Capitol later this summer to adopt the annual bond package. And Lamont has asked them to reconsider tolls, saying the status quo can’t continue. Connecticut will borrow $850 million this coming fiscal year — $75 million more than it averaged over the last two years — for transportation repairs. This borrowing, which is repaid with gas taxes and other revenues from the budget’s Special Transportation Fund, is paired with about $700 million per year in federal transportation grants.