Fix incorrect result of max aggregation fun with collation ci

[xzhangxian1008]

What problem does this PR solve?

Issue Number: close #6807

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• windtalker
• ywqzzy

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[xzhangxian1008]

/cc @windtalker @ywqzzy

[xzhangxian1008]

/run-integration-test

[windtalker]

LGTM

[ywqzzy]

Maybe you can add a ut.

[ywqzzy]

Rest LGTM

[xzhangxian1008]

Maybe you can add a ut.

It's a little bit troublesome.

[xzhangxian1008]

/run-unit-test

[windtalker]

/merge

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.3: #7012.

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In response to a cherrypick label: new pull request created to branch release-6.0: #7013.

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In response to a cherrypick label: new pull request created to branch release-6.5: #7014.

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In response to a cherrypick label: new pull request created to branch release-6.6: #7015.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #7016.

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In response to a cherrypick label: new pull request created to branch release-6.1: #7017.

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In response to a cherrypick label: new pull request created to branch release-6.2: #7018.

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In response to a cherrypick label: new pull request created to branch release-6.3: #7019.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.4: #7020.