TAJO-1093: DateTimeFormat.to_char() is slower than SimpleDateFormat.form...

Details can be found on this line note.
https://github.com/ykrips/tajo/commit/127b2026b8b3cc010cce738706543f606dc69d18#tajo-common-src-main-java-org-apache-tajo-util-datetime-datetimeformat-java-P30
In addition, I found a defect on my patch. When specifying the minimal width on formatString function, it could not be applied.