Bug #51976 LDML collations issue

Problem: caseup_multiply and casedn_multiply members      
were not initialized for a dynamic collation, so          
UPPER() and LOWER() functions returned empty strings.      
Fix: initializing the members properly.

Adding tests:
  mysql-test/r/ctype_ldml.result
  mysql-test/t/ctype_ldml.test

Applying the fix:
  mysys/charset.c

mysql-test/r/ctype_ldml.result

@@ -49,6 +49,15 @@ SELECT * FROM t1 WHERE LOWER(a)=LOWER('N');
 a
 DROP TABLE t1;
 #
+# Bug#51976 LDML collations issue (cyrillic example)
+#
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET utf8 COLLATE utf8_test_ci);
+INSERT INTO t1 (a) VALUES ('Hello');
+SELECT a, UPPER(a), LOWER(a) FROM t1;
+a	UPPER(a)	LOWER(a)
+Hello	HELLO	hello
+DROP TABLE t1;
+#
 # Bug#43827 Server closes connections and restarts
 #
 CREATE TABLE t1 (c1 VARCHAR(10) CHARACTER SET utf8 COLLATE utf8_test_ci);

mysql-test/t/ctype_ldml.test

@@ -45,6 +45,14 @@ INSERT INTO t1 (a) VALUES ('hello!');
 SELECT * FROM t1 WHERE LOWER(a)=LOWER('N');
 DROP TABLE t1;
 
+--echo #
+--echo # Bug#51976 LDML collations issue (cyrillic example)
+--echo #
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET utf8 COLLATE utf8_test_ci);
+INSERT INTO t1 (a) VALUES ('Hello');
+SELECT a, UPPER(a), LOWER(a) FROM t1;
+DROP TABLE t1;
+
 --echo #
 --echo # Bug#43827 Server closes connections and restarts
 --echo #

mysys/charset.c

@@ -245,6 +245,8 @@ static int add_collation(CHARSET_INFO *cs)
       if (cs_copy_data(all_charsets[cs->number],cs))
         return MY_XML_ERROR;
 
+      newcs->caseup_multiply= newcs->casedn_multiply= 1;
+
       if (!strcmp(cs->csname,"ucs2") )
       {
 #if defined(HAVE_CHARSET_ucs2) && defined(HAVE_UCA_COLLATIONS)