HARTFORD, Conn. — The Connecticut Supreme Court on Wednesday grappled with whether a $20 million bond set for a former researcher at the Massachusetts Institute of Technology accused of killing a Yale graduate student is unconstitutionally high and how state judges should go about setting bail amounts.Justices heard just under an hour of arguments by a lawyer for Qinxuan Pan and a state prosecutor. The court did not issue an immediate decision.Pan, 30, is charged with murder in the shooting death of Kevin Jiang on a New …