expression, util: add KeyWithoutTrimRightSpace for collator (#35475)

[ti-srebot]

cherry-pick #35475 to release-5.3
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/35517

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

git push git@github.com:ti-srebot/tidb.git pr/35517:release-5.3-cd731af05a54

---

What problem does this PR solve?

Issue Number: close #35451

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]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Defined2014
• xiongjiwei

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[ti-srebot]

/run-all-tests

[ti-srebot]

@Defined2014 you're already a collaborator in bot's repo.

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/be25829df2dca8d33d7257c9ef88df31cc8543e5

[Defined2014]

/merge

[ti-chi-bot]

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

Commit hash: f5ea9dd

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@ti-srebot: Your PR was out of date, I have automatically updated it for you.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

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[Defined2014]

/run-unit-test

[Defined2014]

/run-unit-test