Revert "Issue #2885413 by quietone, smustgrave, eugene.brit, gambry, mikelutz, renatog, ankithashetty, Etroid, sarathkm, catch, alexpott, berdir, daffie, ghost of drupal past, ProFire, mpdonadio: Timestamp field items are affected by 2038 bug"

This reverts commit 42c849c8.