Daylight saving times are not properly handled during add index

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> create table t (a timestamp);
Query OK, 0 rows affected (0.14 sec)

mysql> SET time_zone = 'Asia/Shanghai';
Query OK, 0 rows affected (0.00 sec)

mysql> insert into t values('1991-07-21 00:00:00');
Query OK, 1 row affected (0.01 sec)

mysql> alter table t add index idx(a);
Query OK, 0 rows affected (2.72 sec)

mysql> admin check table t;
ERROR 8223 (HY000): data inconsistency in table: t, index: idx, handle: 1, index-values:"handle: 1, values: [KindMysqlTime 1991-07-20 23:00:00]" != record-values:"handle: 1, values: [KindMysqlTime 1991-07-21 00:00:00]"

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

Admin check passed.

3. What did you see instead (Required)

Admin check failed.

4. What is your TiDB version? (Required)

master 35d5765