TST: Revisit tests marked as remote data that can now use offline IERS #10457

This is a follow-up of #10311: A reminder that we should revisit some remote data tests that are currently marked as remote data only because they access IERS somehow (e.g., time, coordinates). Now, with astropy.utils.iers.conf.auto_download = False by default in the test suite, these tests no longer needs to be remote data tests as long as they can live with possibly outdated results and have their outputs adjusted accordingly.

cc @mhvk