- Change short weekday names to use only one Chinese character.
(note: this is a somewhat misunfortunate compromise due to the fact
that some applications are using short buffer for weekday names,
and in ~1905 when 星期 system was created to replace the traditional
七曜 system, which can use 日月火水木金土 to represent Sunday through
Saturday with just one character without any confusion).
- for zh_CN locales: use Arabic numerals for month names, matching the
practice of all other CJK locales
- Regenerate zh_CN.{GB2312,GBK} locales from zh_CN.UTF-8.
Reported by: ygy
Reviewed by: kevlo
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D18689
