Texas Gov. Greg Abbott and top state lawmakers shifted around roughly $1 billion in federal coronavirus aid to help pay for their campaign to arrest migrants at the U.S.-Mexico border, exposing gaps in a law meant to bolster the country’s response to the ongoing pandemic.Relying on the availability of generous federal relief funds, Texas repeatedly in recent months rerouted state money toward its controversial immigration crackdown — all without leaving a massive hole in its budget. But critics say the money would have been put to better use tending to a public health crisis that has killed more than 86,000 ...