`ADMIN CHECK` cannot work well when index name has `

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

```
mysql> use test;
Database changed
mysql> create table t (id int, key ```idx`(id));
Query OK, 0 rows affected (0.06 sec)

mysql> admin check table t;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your TiDB version for the right syntax to use line 1 column 185 near "idx`) where 0 = 0 group by ((cast(crc32(md5(concat_ws(0x2, `_tidb_rowid`))) as signed) - 0) div 1 % 1024)"
```

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

### 3. What did you see instead (Required)

### 4. What is your TiDB version? (Required)