Deep nested OR expressions caused compile oom

[chrysan]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Run a sql with deep nested OR expressions.

We need:

1. memory track and threshold

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

SQL runs normally or is killed due to memory quota.

3. What did you see instead (Required)

TiDB oom.
If we look into the oom dump:

4. What is your TiDB version? (Required)

v6.5

[chrysan]

We need:

1. track the memory of the exprs' hashCode and make the sql killed when exceeds memory threshold
2. need a new implementation of ReHashCode which is more memory efficient