MDEV-5675 - Performance: my_hash_sort_bin is called too often

Reduced number of my_hash_sort_bin() calls from 4 to 1 per query.
Reduced number of memory accesses done by my_hash_sort_bin().

Details:
- let MDL subsystem use pre-calculated hash value for hash
  inserts and deletes
- let table cache use pre-calculated MDL hash value
- MDL namespace is excluded from hash value calculation, so that
  hash value can be used by table cache as is
- hash value for MDL is calculated as resulting hash value + MDL
  namespace
- extended hash implementation to accept user defined hash function

storage/maria/maria_read_log.c

@@ -301,7 +301,7 @@ get_one_option(int optid __attribute__((unused)),
     if (!my_hash_inited(&tables_to_redo))
     {
       my_hash_init2(&tables_to_redo, 16, &my_charset_bin,
-                    16, 0, 0, my_hash_get_string, 0, HASH_UNIQUE);
+                    16, 0, 0, my_hash_get_string, 0, 0, HASH_UNIQUE);
     }
     do
     {