One second off with pre epoch dates #894

public void testEpoch() {
    assertParsedRfc3339(
        "1970-01-01T00:00:00.000Z", SecondsAndNanos.ofSecondsAndNanos(0, 0));
  }

  public void testOneSecondBeforeEpoch() {
    assertParsedRfc3339(
        "1969-12-31T23:59:59.000Z", SecondsAndNanos.ofSecondsAndNanos(-1, 0));
  }