fix handler test failures on s390x

keyinfo->name is a LEX_CSTRING

also, fix the location comment (that applied to ext_key_part_map)

sql/sql_handler.cc

@@ -670,7 +670,7 @@ mysql_ha_fix_cond_and_key(SQL_HANDLER *handler,
             (HA_READ_NEXT | HA_READ_PREV | HA_READ_RANGE)) == 0))
       {
         my_error(ER_KEY_DOESNT_SUPPORT, MYF(0),
-                 table->file->index_type(handler->keyno), keyinfo->name);
+                 table->file->index_type(handler->keyno), keyinfo->name.str);
         return 1;
       }
 

sql/structs.h

@@ -109,8 +109,8 @@ typedef struct st_key {
       pk2 is explicitly present in idx1, it is not in the extension, so
       ext_key_part_map.is_set(1) == false
   */
-  LEX_CSTRING name;
   key_part_map ext_key_part_map;
+  LEX_CSTRING name;
   uint  block_size;
   enum  ha_key_alg algorithm;
   /*