The into clause is missing in prepare into outfile

[keeplearning20221]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

CREATE TABLE t (
c int DEFAULT NULL
);
insert into t value(1);
prepare stmt from "select c from t limit 1 into outfile 'text'";

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

3. What did you see instead (Required)

4. What is your TiDB version? (Required)

mysql> SELECT tidb_version();
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version() |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v7.6.0-alpha-372-g0fd779c623
Edition: Community
Git Commit Hash: 0fd779c
Git Branch: master
UTC Build Time: 2023-12-05 02:29:50
GoVersion: go1.21.1
Race Enabled: false
Check Table Before Drop: false
Store: unistore