MDEV-25474 Background thread returns uninitialized statistics

		to mysql interpreter

InnoDB returns uninitialized statistics to mysql interpreter
when background thread is opening the table. So it leads to
assertion failure. In that case, InnoDB avoid sending
innodb statistics information to mysql interpreter.

storage/innobase/handler/ha_innodb.cc

@@ -6261,9 +6261,10 @@ ha_innobase::open(const char* name, int, uint)
 
 	innobase_copy_frm_flags_from_table_share(ib_table, table->s);
 
+	const bool bk_thread = THDVAR(thd, background_thread);
 	/* No point to init any statistics if tablespace is still encrypted
 	or if table is being opened by background thread */
-	if (THDVAR(thd, background_thread)) {
+	if (bk_thread) {
 	} else if (ib_table->is_readable()) {
 		dict_stats_init(ib_table);
 	} else {
@@ -6515,7 +6516,10 @@ ha_innobase::open(const char* name, int, uint)
 		}
 	}
 
-	info(HA_STATUS_NO_LOCK | HA_STATUS_VARIABLE | HA_STATUS_CONST);
+	if (!bk_thread) {
+		info(HA_STATUS_NO_LOCK | HA_STATUS_VARIABLE | HA_STATUS_CONST);
+	}
+
 	DBUG_RETURN(0);
 }