WASHINGTON — Chief Justice John Roberts has declined a request from the Senate Judiciary Committee to testify at a hearing next week on ethical standards at the court, instead providing the panel with a statement of ethics reaffirmed by the court’s nine justices.Senate Judiciary Committee Chairman Dick Durbin, D-Ill., invited Roberts’ testimony last week, saying that there had been a “steady stream of revelations” regarding Supreme Court justices “falling short of ethical standards …