runtime error: index out of range [7] with length 4

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

```sql
CREATE TABLE t0(c0 FLOAT);
INSERT INTO t0(c0) VALUES (1);
SELECT * FROM t0 GROUP BY t0.c0, (CASE ((t0.c0)>=(t0.c0)) WHEN SIN(t0.c0) THEN NULL ELSE t0.c0 END);
```

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

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

ERROR 1105 (HY000) at line 9: runtime error: index out of range [7] with length 4

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

| Release Version: v7.1.0
Edition: Community
Git Commit Hash: 635a4362235e8a3c0043542e629532e3c7bb2756
Git Branch: heads/refs/tags/v7.1.0
UTC Build Time: 2023-05-30 10:58:57
GoVersion: go1.20.3
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: unistore |