By Andrew Chung WASHINGTON (Reuters) -U.S. Supreme Court justices on Tuesday grappled with President Joe Biden’s bid to rescind a hardline immigration policy begun under his predecessor Donald Trump that forced tens of thousands of migrants to stay in Mexico to await U.S. hearings on their asylum claims. The justices heard oral arguments in a Biden administration appeal of a lower court ruling reinstating Trump’s “remain in Mexico” policy after the Republican-led states of Texas and Missouri sued to maintain the program. Biden suspended Trump’s policy, which had changed longstanding U.S. pract…