drop stats remain the "topn" info in mysql.stats_top_n

[lzmhhh123]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create table t (c1 varchar(20), c2 varchar(20));
insert into t values("1","1"),("2","2"),("3","3"),("4","4");
insert into t select * from t;
insert into t select * from t;
analyze table t;
drop stats t;
select table_id, hist_id from mysql.stats_top_n;

2. What did you expect to see? (Required)

The mysql.stats_top_n should be empty.

3. What did you see instead (Required)

There are some topn info in the table stats_top_n for table t.

4. Affected version (Required)

v3.0.0, v4.0.0, v3.1.0

5. Root Cause Analysis

drop stats didn't delete it.