executor: global index scan returns wrong result when specify partition

[L-maple]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

premise:
set enable-global-index = true in config/config.toml.example

SQL:

use test
drop table if exists p;
create table p (id int, c int) partition by range (c) (
    partition p0 values less than (4),
    partition p1 values less than (7),
    partition p2 values less than (10));
alter table p add unique idx(id);
insert into p values (1,3), (3,4), (5,6), (7,9);
select id from p partition(p0) use index (idx);

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

1

3. What did you see instead (Required)

1
3
5
7

4. What is your TiDB version? (Required)

----+
| Release Version: v6.7.0-alpha-139-g6c1674cb1-dirty
Edition: Community
Git Commit Hash: 6c1674c
Git Branch: local/fix_truncate_drop_partition_for_global_index
UTC Build Time: 2023-03-02 03:19:49
GoVersion: go1.19.4
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: unistore |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)