MFC r342614, r342633

MFC r342614, r342633

r342614:
Properly set svn:mimetype for zh_CN.UTF-8.src.

r342633:
Fix various issues with Chinese locales:

 - 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
Differential Revision:	https://reviews.freebsd.org/D18689