Reverted the fix for bug #25830 because of omissions and non-complete test

case.

mysql-test/r/lowercase_utf8.result

-set names utf8;
-create table `Ö` (id int);
-show tables from test like 'Ö';
-Tables_in_test (Ö)
-ö
-show tables from test like 'ö';
-Tables_in_test (ö)
-ö
-drop table `Ö`;

mysql-test/t/lowercase_utf8-master.opt

---lower-case-table-names=1 --character-set-server=utf8
-
-
-

mysql-test/t/lowercase_utf8.test

-#
-# Bug#25830 SHOW TABLE STATUS behaves differently depending on table name
-#
-set names utf8;
-create table `Ö` (id int);
-show tables from test like 'Ö';
-show tables from test like 'ö';
-drop table `Ö`;
-

sql/sql_show.cc

@@ -287,17 +287,11 @@ find_files(THD *thd, List<char> *files, const char *db,
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   uint col_access=thd->col_access;
 #endif
-  uint wild_length= 0;
   TABLE_LIST table_list;
   DBUG_ENTER("find_files");
 
-  if (wild)
-  {
-    if (!wild[0])
-      wild= 0;
-    else
-      wild_length= strlen(wild);
-  }
+  if (wild && !wild[0])
+    wild=0;
 
   bzero((char*) &table_list,sizeof(table_list));
 
@@ -346,10 +340,7 @@ find_files(THD *thd, List<char> *files, const char *db,
       {
 	if (lower_case_table_names)
 	{
-          if (my_wildcmp(files_charset_info,
-                         file->name, file->name + strlen(file->name),
-                         wild, wild + wild_length,
-                         wild_prefix, wild_one, wild_many))
+	  if (wild_case_compare(files_charset_info, file->name, wild))
 	    continue;
 	}
 	else if (wild_compare(file->name,wild,0))