AMARILLO, Texas — A federal judge in Texas will hear arguments Wednesday in a high-stakes court case that could threaten access to abortion medication and blunt the authority of U.S. drug regulators.Judge Matthew Kacsmaryk is weighing a lawsuit from Christian conservatives aimed at overturning the Food and Drug Administration’s more than 2-decade-old approval of the abortion pill mifepristone. The drug, when used with a second pill, has become the most common method of abortion in the U.S.There is essentially …