GH-47105: [Statistics][C++] Implement Statistics specification attribute ARROW:row_count:approximate

[andishgar]

Rationale for this change

Implement the statistics specification attribute ARROW:row_count:approximate.

What changes are included in this PR?

Implement the statistics specification attribute ARROW:row_count:approximate with relevant tests.

Are these changes tested?

Yes, I ran the related tests.

Are there any user-facing changes?

Yes, this adds the arrow::ArrayStatistics::row_count attribute.

• GitHub Issue: [Statistics][C++] Implement Statistics specification attribute ARROW:row_count:approximate #47105

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

Opening GitHub issues ahead of time contributes to the Openness of the Apache Arrow project.

Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - Contributing Overview

[github-actions]

⚠️ GitHub issue #47105 has been automatically assigned in GitHub to PR creator.

[andishgar]

Hi @kou, could you take a look at this?

[kou]

+1