With coronavirus cases surging and families hoping to gather safely for Thanksgiving, long lines to get tested have reappeared across the U.S. — a reminder that the nation’s testing system remains unable to keep pace with the virus. The delays are happening as the country braces for winter weather, flu season and holiday travel, all of which are expected to amplify a U.S. outbreak … Laboratories warned that continuing shortages of key supplies are likely to create more bottlenecks and delays, especially as cases rise across the nation and people rush to get tested before reuniting with relatives.