expression: Add column nullability checking before "refine args"

[youwithouto]

What problem does this PR solve?

Issue Number: close #16788

This PR contains the same logic as PR 20040 which is a fix for Issue 16679

• The same logic can fix both issues, while the two issues are "picked" by different persons.

Problem Summary:
When comparing a nullable integer column with a float, the output is not consistent with that of MySQL.

What is changed and how it works?

What's Changed:

Added column nullability checking

• If the column is nullable, use raw args directly;
• else, refine args

How it Works:

N/A

Related changes

N/A

Check List

Tests

• Unit test
• Integration test

Side effects

• Breaking backward compatibility
  For some of the statements, the corresponding execution plans are changed

Release note

• No release note

[sre-bot]

No release note, Please follow https://github.com/pingcap/community/blob/master/contributors/release-note-checker.md

[zz-jason]

I'm going to close this PR since it hasn't been updated for a long time. feel free to reopen if you want to continue with it. thanks for your contribution.