*: use generics to improve Clamp

[hawkingrei]

What problem does this PR solve?

Issue Number: close #34588

Problem Summary:

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test

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:

• disksing
• tisonkun

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[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/9dd702db6eee9da60f7057774762ac0bee87c604

[tisonkun]

/merge

[ti-chi-bot]

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

Commit hash: e1beceb

[hawkingrei]

/run-build

[hawkingrei]

/run-mysql-test

[ti-chi-bot]

@hawkingrei: Your PR was out of date, I have automatically updated it for you.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