When a TTS image backup taken with full-locking was restored by streaming the image to mysqlbackup, the restore failed due to a tail magic mismatch. (Bug #37196546)

After a backup was finished, the values of the server's status variables Com_stmt_prepare and Com_stmt_close did not match. It was because mysqlbackup, after using prepared statements to query the server, closed its connection to the server prematurely. With this fix, Com_stmt_close is also incremented before mysqlbackup disconnects from the server. (Bug #34624351)