MDEV-7910: innodb.binlog_consistent fails sporadically in buildbot

The test case was missing --source include/wait_for_binlog_checkpoint.inc.
So it could occasionally fail if the checkpoint managed to occur just at the
right point in time between fetching the two binlog positions to compare.

mysql-test/suite/innodb/t/binlog_consistent.test

@@ -103,6 +103,7 @@ eval INSERT INTO t3 VALUES (11, '$bigdata');
 # So here, we check that the values are consistent with SHOW MASTER STATUS,
 # which uses a different code path and did not have the bug.
 
+--source include/wait_for_binlog_checkpoint.inc
 --let $snap_file= query_get_value(SHOW STATUS LIKE 'binlog_snapshot_file', Value, 1)
 --let $snap_pos= query_get_value(SHOW STATUS LIKE 'binlog_snapshot_position', Value, 1)