SPRINGFIELD — Illinois courts and lawmakers have broadly reexamined how they treat juvenile offenders over the last few years.They have called for more lenient rules on shackling juveniles in court.They have limited when youth can be tried as adults in criminal cases.And they have ruled those given life in prison as juveniles should have their sentences reconsidered.Now the Illinois Supreme Court has taken another step in that direction, ruling that de facto mandatory life sentences for juveniles are unconstitutional …