NEW YORK/SAN FRANCISCO — At the height of President Barack Obama’s crackdown on illegal crossings from Mexico seven years ago, San Diego’s federal courts were so clogged that immigrants arrested near the border sometimes slept on the floor of border patrol stations for days before seeing a judge.Now, with Attorney General Jeff Sessions’ vow to criminally prosecute all those caught entering the United States illegally, which he reiterated on Monday, some judges and attorneys worry the courts are headed toward similar backlogs.In Arizona, U.S.