*: avoid copy in the SortSampleItems (#48683)

[ti-chi-bot]

This is an automated cherry-pick of #48683

What problem does this PR solve?

Issue Number: ref #47275

Problem Summary:

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

before

$ go test -benchmem -run=^$ -bench ^BenchmarkBuildHistAndTopN$ github.com/pingcap/tidb/pkg/statistics
goos: darwin
goarch: arm64
pkg: github.com/pingcap/tidb/pkg/statistics
BenchmarkBuildHistAndTopN-8            1        1363438291 ns/op        72031328 B/op    4000055 allocs/op

after

$ go test -benchmem -run=^$ -bench ^BenchmarkBuildHistAndTopN$ github.com/pingcap/tidb/pkg/statistics
goos: darwin
goarch: arm64
pkg: github.com/pingcap/tidb/pkg/statistics
BenchmarkBuildHistAndTopN-8            1        1352474167 ns/op        64027744 B/op    4000054 allocs/op

• No need to test

  • I checked and no code files have been changed.

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]

This cherry pick PR is for a release branch and has not yet been approved by triage owners.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-chi-bot]

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[ti-chi-bot]

@ti-chi-bot: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
idc-jenkins-ci-tidb/unit-test	5b487ff	link	true	/test unit-test
idc-jenkins-ci-tidb/check_dev_2	5b487ff	link	true	/test check-dev2
idc-jenkins-ci-tidb/build	5b487ff	link	true	/test build
idc-jenkins-ci-tidb/mysql-test	5b487ff	link	true	/test mysql-test
idc-jenkins-ci-tidb/check_dev	5b487ff	link	true	/test check-dev

Full PR test history. Your PR dashboard.

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