GH-48355: [Python] Remove obsolete snprintf workaround for Python 3.9

[HyukjinKwon]

Rationale for this change

https://github.com/apache/arrow/commit/e9b9042a058333b68849a640b510e94413a29d91 added the workaround for Python 3.9 on Windows. However, PyArrow dropped Python 3.9 at https://github.com/apache/arrow/commit/aedb752762174b7971fe13a42d2b925bd76da3be. Per https://github.com/python/cpython/commit/e822e37946f27c09953bb5733acf3b07c2db690f, this should be fine to be removed.

What changes are included in this PR?

This PR proposes to remove obsolete snprintf workaround for Python 3.9 on Windows.

Are these changes tested?

I tested locally but do not have Windows environment. I will rely on CI.

Are there any user-facing changes?

No.

• GitHub Issue: #48355

[HyukjinKwon]

For reviewers I am trying to get used to the dev, reading documentation and code bit by bit so I happened to create a lot of minor PRs 🙏 .

[AlenkaF]

These kind of contributions are very welcome! As for this specific PR, though it is a minimal change, can you create an issue to track what you are removing?

[raulcd]

Thanks for the contributions! echoing @AlenkaF see our definition for MINOR here: https://github.com/apache/arrow/blob/main/CONTRIBUTING.md#minor-fixes

[HyukjinKwon]

Thanks, will do

[github-actions[bot]]

:warning: GitHub issue #48355 has been automatically assigned in GitHub to PR creator.

[HyukjinKwon]

@wjones127, would you mind taking a quick look please when you find some time?