expression: make count distinct multi column aware of new collation (#27111)

[ti-srebot]

cherry-pick #27111 to release-5.0
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# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/27507

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git push git@github.com:ti-srebot/tidb.git pr/27507:release-5.0-08995d915d3d

---

What problem does this PR solve?

Issue Number: close #27091

Problem Summary:

As the issue described.

What is changed and how it works?

Proposal: xxx

What's Changed:

How it Works:

Use the collation info when calling UpdatePartialResult in countOriginalWithDistinct and approxCountDistinctOriginal

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 bug that count disctinct on multi-columns return wrong result when new collation is on.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• qw4990
• wjhuang2016

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[ti-srebot]

/run-all-tests

[ti-srebot]

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

[zhouqiang-cl]

/merge

[ti-chi-bot]

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

Commit hash: 23cfb61

[ti-chi-bot]

@ti-srebot: Your PR was out of date, I have automatically updated it for you.

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[ti-chi-bot]

@ti-srebot: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.