WASHINGTON — The Supreme Court said Thursday that a federal appeals court was wrong when it ordered Michigan to retry or release a convicted murderer because his rights were violated when he was shackled at trial.In a decision that split the court 6-3 along ideological lines, the court’s conservative majority said that a federal appeals court was wrong to apply only one legal test to conclude that the man should be released or retried.The justices said the appeals court should have applied two different legal …