GH-48848: [Dev] Remove obsolete Java, Go, and Swift entries from .gitignore

[HyukjinKwon]

Rationale for this change

The Java, Go, and Swift implementations have been moved to separate repositories, but their .gitignore entries were not cleaned up:

• Java removed in [Java] Remove java/ #44945 3a46cc2
• Go removed in [Go] Remove go/ #43879 e62fbaa
• Swift removed in [Swift] Remove swift folder from this repository #46803 a77bfec

What changes are included in this PR?

Remove obsolete Java, Go, and Swift entries from .gitignore.

Are these changes tested?

No I did not test.

Are there any user-facing changes?

No, dev-only.

• GitHub Issue: [Dev] Remove obsolete Java, Go, and Swift entries from .gitignore #48848

[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 #48848 has been automatically assigned in GitHub to PR creator.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 3 benchmarking runs that have been run so far on merge-commit 9866071.

There weren't enough matching historic benchmark results to make a call on whether there were regressions.

The full Conbench report has more details.