collation_connection affects the passing of constants cause wrong query plan

## Bug Report

collation_connection affects the passing of constants cause wrong query plan
### 1. Minimal reproduce step (Required)
```
CREATE TABLE `t2` (
`id1` char(8) NOT NULL COMMENT '编号',
`id2` varchar(180) NOT NULL COMMENT '姓名',
`id3` varchar(12) NOT NULL COMMENT '岗位编号',
`id4` char(9) NOT NULL COMMENT '机构编号',
`id5` varchar(10) NOT NULL COMMENT '角色编号',
`id6` varchar(60) DEFAULT NULL COMMENT '登录名',
PRIMARY KEY (`id1`,`id2`,`id3`) /*T![clustered_index] NONCLUSTERED */
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
CREATE TABLE `t1` (
`id1` varchar(200) NOT NULL COMMENT '编号',
`id2` varchar(200) DEFAULT NULL COMMENT '账号',
`id3` varchar(600) DEFAULT NULL COMMENT '姓名',
`id4` varchar(600) DEFAULT NULL COMMENT '电话',
PRIMARY KEY (`id1`) /*T![clustered_index] NONCLUSTERED */
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
set collation_connection=utf8_general_ci;

```

### 2. What did you expect to see? (Required)
```
mysql> explain format='verbose' SELECT t.id1, t.id2, t.id3 FROM t1 t
-> JOIN t2
-> ON t.id1 = t2.id1
-> WHERE t2.id1 = '63812828';
+-----------------------------+---------+---------+-----------+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
| id | estRows | estCost | task | access object | operator info |
+-----------------------------+---------+---------+-----------+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
| IndexJoin_12 | 1.25 | 38.15 | root | | inner join, inner:IndexReader_11, outer key:test.t1.id1, inner key:test.t2.id1, equal cond:eq(test.t1.id1, test.t2.id1) |
| ├─Point_Get_38(Build) | 1.00 | 5.60 | root | table:t1, index:PRIMARY(id1) | |
| └─IndexReader_11(Probe) | 1.25 | 9.11 | root | | index:IndexRangeScan_10 |
| └─IndexRangeScan_10 | 1.25 | 0.00 | cop[tikv] | table:t2, index:PRIMARY(id1, id2, id3) | range: decided by [eq(test.t2.id1, test.t1.id1)], keep order:false, stats:pseudo |
+-----------------------------+---------+---------+-----------+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
4 rows in set, 1 warning (0.00 sec)
```
### 3. What did you see instead (Required)
```
mysql> explain format='verbose' SELECT /*+ INL_JOIN(t2) */ t.id1, t.id2, t.id3 FROM t1 t use index(PRIMARY)
-> JOIN t2
-> ON t.id1 = t2.id1
-> WHERE t2.id1 = '63812828';
+------------------------------------+----------+-----------+-----------+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
| id | estRows | estCost | task | access object | operator info |
+------------------------------------+----------+-----------+-----------+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
| IndexJoin_12 | 12.50 | 399770.41 | root | | inner join, inner:IndexReader_11, outer key:test.t1.id1, inner key:test.t2.id1, equal cond:eq(test.t1.id1, test.t2.id1) |
| ├─IndexLookUp_22(Build) | 10000.00 | 229828.94 | root | | |
| │ ├─IndexFullScan_20(Build) | 10000.00 | 555000.00 | cop[tikv] | table:t, index:PRIMARY(id1) | keep order:false, stats:pseudo |
| │ └─TableRowIDScan_21(Probe) | 10000.00 | 555000.00 | cop[tikv] | table:t | keep order:false, stats:pseudo |
| └─IndexReader_11(Probe) | 0.00 | 7.34 | root | | index:Selection_10 |
| └─Selection_10 | 0.00 | 0.00 | cop[tikv] | | eq(test.t2.id1, "63812828") |
| └─IndexRangeScan_9 | 1.25 | 0.00 | cop[tikv] | table:t2, index:PRIMARY(id1, id2, id3) | range: decided by [eq(test.t2.id1, test.t1.id1)], keep order:false, stats:pseudo |
+------------------------------------+----------+-----------+-----------+----------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
7 rows in set (0.00 sec)
```
### 4. What is your TiDB version? (Required)

v6.1.1