MDEV-30630 locale: Chinese error messages for ZH_CN

MDEV-28227 added the error messages in simplified characters.
Lets use these for those running a zh_CN profile.

From Haidong Ji in the MDEV, Taiwan/Hong Kong (zh_TW/zh_HK)
would expect traditional characters so this is left for when
we have these.

mysql-test/main/locale.result

@@ -306,3 +306,13 @@ date_format('2001-01-06', '%w %a %W', 'de_CH')
 select date_format('2001-09-01', '%c %b %M', 'de_CH');
 date_format('2001-09-01', '%c %b %M', 'de_CH')
 9 Sep September
+#
+#  MDEV-30630 locale: Chinese error message for ZH_CN
+#
+SET lc_messages=ZH_CN;
+SELECT x;
+ERROR 42S22: 未知列'x'在'field list'
+SET lc_messages=DEFAULT;
+#
+# End of 10.4 tests
+#

mysql-test/main/locale.test

@@ -181,3 +181,17 @@ select date_format('2001-10-01', '%c %b %M', 'rm_CH');
 select date_format('2001-12-01', '%c %b %M', 'rm_CH');
 select date_format('2001-01-06', '%w %a %W', 'de_CH');
 select date_format('2001-09-01', '%c %b %M', 'de_CH');
+
+--echo #
+--echo #  MDEV-30630 locale: Chinese error message for ZH_CN
+--echo #
+
+SET lc_messages=ZH_CN;
+--error ER_BAD_FIELD_ERROR
+SELECT x;
+
+SET lc_messages=DEFAULT;
+
+--echo #
+--echo # End of 10.4 tests
+--echo #

mysql-test/suite/plugins/r/locales.result

@@ -57,7 +57,7 @@ ID	NAME	DESCRIPTION	MAX_MONTH_NAME_LENGTH	MAX_DAY_NAME_LENGTH	DECIMAL_POINT	THOU
 53	uk_UA	Ukrainian - Ukraine	8	9	,	.	ukrainian
 54	ur_PK	Urdu - Pakistan	6	6	.	,	english
 55	vi_VN	Vietnamese - Vietnam	16	11	,	.	english
-56	zh_CN	Chinese - Peoples Republic of China	3	3	.	,	english
+56	zh_CN	Chinese - Peoples Republic of China	3	3	.	,	chinese
 57	zh_TW	Chinese - Taiwan	3	2	.	,	english
 58	ar_DZ	Arabic - Algeria	6	8	.	,	english
 59	ar_EG	Arabic - Egypt	6	8	.	,	english
@@ -170,7 +170,7 @@ Id	Name	Description	Error_Message_Language
 53	uk_UA	Ukrainian - Ukraine	ukrainian
 54	ur_PK	Urdu - Pakistan	english
 55	vi_VN	Vietnamese - Vietnam	english
-56	zh_CN	Chinese - Peoples Republic of China	english
+56	zh_CN	Chinese - Peoples Republic of China	chinese
 57	zh_TW	Chinese - Taiwan	english
 58	ar_DZ	Arabic - Algeria	english
 59	ar_EG	Arabic - Egypt	english

sql/sql_locale.cc

@@ -29,7 +29,7 @@
 
 enum err_msgs_index
 {
-  en_US= 0, cs_CZ, da_DK, nl_NL, et_EE, fr_FR, de_DE, el_GR, hu_HU, it_IT,
+  en_US= 0, zh_CN, cs_CZ, da_DK, nl_NL, et_EE, fr_FR, de_DE, el_GR, hu_HU, it_IT,
   ja_JP, ko_KR, no_NO, nn_NO, pl_PL, pt_PT, ro_RO, ru_RU, sr_RS,  sk_SK,
   es_ES, sv_SE, uk_UA, hi_IN
 } ERR_MSGS_INDEX;
@@ -38,6 +38,7 @@ enum err_msgs_index
 MY_LOCALE_ERRMSGS global_errmsgs[]=
 {
   {"english", NULL},
+  {"chinese", NULL},
   {"czech", NULL},
   {"danish", NULL},
   {"dutch", NULL},
@@ -2095,7 +2096,7 @@ MY_LOCALE my_locale_zh_CN
   '.',        /* decimal point zh_CN */
   ',',        /* thousands_sep zh_CN */
   "\x03",     /* grouping      zh_CN */
-  &global_errmsgs[en_US]
+  &global_errmsgs[zh_CN]
 );
 /***** LOCALE END zh_CN *****/