should skip privilege check when execute foreign key cascade

[crazycs520]

Issue

Reproduce

set @@global.tidb_enable_foreign_key=1;
set @@foreign_key_checks=1;
create table t1 (id int key);
create table t2 (id int key, foreign key fk (id) references t1(id) ON DELETE CASCADE ON UPDATE CASCADE);
insert into t1 values (1), (2), (3);
insert into t2 values (1), (2), (3);

create user 'u1'@'%' identified by '';
grant select, delete on test.t1 to 'u1'@'%';

Then use user u1 to execute following SQL:

set @@foreign_key_checks=1;
delete from t1 where id=1;

Current TiDB will return error:

> delete from t1 where id=1;
(1142, "SELECT command denied to user 'u1'@'%' for table 't2'")

But MySQL will execute success:

> delete from t1 where id=1;
Query OK, 1 row affected
Time: 0.021s
t> select version();
+-----------+
| version() |
+-----------+
| 8.0.30    |
+-----------+
1 row in set

TiDB version:

***************************[ 1. row ]***************************
tidb_version() | Release Version: v6.5.0-alpha-206-gfa7cf31eff
Edition: Community
Git Commit Hash: fa7cf31eff6952408b023a634ccb403710b5de89
Git Branch: master
UTC Build Time: 2022-12-01 04:32:26
GoVersion: go1.19.3
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: unistore