builtin functions compatibility problem with different version of mysql

[xiongjiwei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

MySQL has changed its behavior at v8.0.24 for some builtin functions:

field
instr
locate
insert

which will cause a different result. We not following the version before 8.0.24.

MySQL commit mysql/mysql-server@997c747

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

3. What did you see instead (Required)

4. What is your TiDB version? (Required)