MDEV-24487 Error after update to 10.5.8 on CentOS-8: DBD::mysql::st execute failed: Unknown MySQL error

The problem happened because the the new client capability flag
CLIENT_EXTENDED_METADATA was not put into the cache entry key.
So results cached by a new client were sent to the old client (and vica versa)
with a mis-matching metadata, which made the client abort the connection on
an unexpected result set metadata packet format.

The problem was caused by the patch for:
  MDEV-17832 Protocol: extensions for Pluggable types and JSON, GEOMETRY
which forgot to adjust the query cache code.

Fix:

- Adding a new member Query_cache_query_flags::client_extended_metadata,
  so only clients with equal CLIENT_EXTENDED_METADATA flag values can
  reuse results.

- Adding a new column CLIENT_EXTENDED_METADATA into
  INFORMATION_SCHEMA.QUERY_CACHE_INFO (privided by the qc_info plugin).

mysql-test/suite/plugins/t/qc_info_init.inc

@@ -30,5 +30,5 @@ select * from t1;
 set time_zone= @time_zone, default_week_format= @default_week_format, character_set_client= @character_set_client,character_set_results= @character_set_results, sql_mode= @sql_mode, div_precision_increment= @div_precision_increment, lc_time_names= @lc_time_names, autocommit= @autocommit, group_concat_max_len= @group_concat_max_len, max_sort_length= @max_sort_length;
 
 --sorted_result
---replace_column 5 # 19 # 23 #
+--replace_column 5 # 20 # 24 #
 select * from information_schema.query_cache_info;