planner: prune hash partition should consider unsigned flag (#27098)

[ti-srebot]

cherry-pick #27098 to release-5.1
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# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/27164

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

git push git@github.com:ti-srebot/tidb.git pr/27164:release-5.1-0e48cb22a9d8

---

What problem does this PR solve?

Issue Number: close #26569

prune hash partition should consider unsigned flag

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

fix a bug that query on hash partition table return wrong reslut

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• qw4990
• tiancaiamao

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[ti-srebot]

/run-all-tests

[ti-srebot]

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

[qw4990]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 1cca41a

[xiongjiwei]

/merge