mtr: innodb_stats_dropped_locked cleanup

As discovered in later test, this test doesn't remove
the innodb_{index,table}_stats entries generated
in the test upon completion.

mysql-test/suite/innodb/r/innodb_stats_drop_locked.result

@@ -43,3 +43,5 @@ innodb_stats_drop_locked
 innodb_stats_drop_locked
 innodb_stats_drop_locked
 innodb_stats_drop_locked
+DELETE FROM mysql.innodb_index_stats WHERE database_name='test' AND table_name='innodb_stats_drop_locked';
+DELETE FROM mysql.innodb_table_stats WHERE database_name='test' AND table_name='innodb_stats_drop_locked';

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

@@ -56,6 +56,8 @@ WHERE table_name='innodb_stats_drop_locked';
 SELECT table_name FROM mysql.innodb_index_stats
 WHERE table_name='innodb_stats_drop_locked';
 
+DELETE FROM mysql.innodb_index_stats WHERE database_name='test' AND table_name='innodb_stats_drop_locked';
+DELETE FROM mysql.innodb_table_stats WHERE database_name='test' AND table_name='innodb_stats_drop_locked';
 --disable_query_log
 call mtr.add_suppression("Unable to delete statistics for table test.innodb_stats_drop_locked: Lock wait timeout. They can be deleted later using DELETE FROM mysql.innodb_index_stats WHERE database_name");
 --enable_query_log