ddl: Fix for unsigned partitioning expressions (#36830)

[ti-srebot]

cherry-pick #36830 to release-5.2
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/37214

After apply modifications, you can push your change to this PR via:

git push [email protected]:ti-srebot/tidb.git pr/37214:release-5.2-a1d135607203

---

What problem does this PR solve?

Issue Number: close #35827

Problem Summary:

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

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[ti-srebot]

/run-all-tests

[ti-chi-bot]

@ti-srebot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-srebot]

@mjonss you're already a collaborator in bot's repo.

[VelocityLight]

This pull request is closed because it's related version has closed automatic cherry-picking.
If it's still needed, you can reopen it or just regenerate it using bot,
see:

• https://prow.tidb.io/command-help#cherrypick
• https://book.prow.tidb.net/#/plugins/cherrypicker

You can find more details at:

• https://internals.tidb.io/t/topic/785