Use StandardCharsets instead of String overload in TextOutputFormat

private static final String utf8 = "UTF-8";
private static final byte[] newline;
static {
  try {
    newline = "\n".getBytes(utf8);
  } catch (UnsupportedException uee) {
    threw new IllegalArgumentException("can't find " + utf8 + " encoding");
  }
}

private static final byte[] newline = "\n".getBytes(StandardCharsets.UTF_8);