SPRINGFIELD — A state law on liability, the Joint Tortfeasor Contribution Act, has two policy goals: encourage settlements and divvy up damages equally among the parties in a lawsuit.But those aims can come into conflict, and the state’s highest court in one of its most recent pronouncements again had trouble striking a balance.A split court upheld a settlement between a man who caused a crash while under the influence of cocaine and the woman who was permanently injured because of the collision.The issue is …