WASHINGTON — Conservative Supreme Court justices on Wednesday voiced support for weakening the power of federal regulators, but it was not clear whether a majority would overturn a major 40-year-old decision.Billions of dollars are potentially at stake in front of a court that, like the rest of the federal judiciary, was remade during Donald Trump’s presidency by conservative interests that were motivated as much by weakening the regulatory state as social issues including abortion.The court heard three and a …