Bug 1878868 - Create TestSetup helper: Test classes A-C (fix for legacy APIs)

[sv-ohorvath]

Added the API level condition and re-ran the tests on the legacy API devices: matrix link.
Everything passed.

Pull Request checklist

• Quality: This PR builds and passes detekt/ktlint checks (A pre-push hook is recommended)
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry or does not need one
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features

After merge

• Breaking Changes: If this is a breaking Android Components change, please push a draft PR on Reference Browser to address the breaking issues.

To download an APK when reviewing a PR (after all CI tasks finished running):

1. Click on Checks at the top of the PR page.
2. Click on the firefoxci-taskcluster group on the left to expand all tasks.
3. Click on the build-apk-{fenix,focus,klar}-debug task you're interested in.
4. Click on View task in Taskcluster in the new DETAILS section.
5. The APK links should be on the right side of the screen, named for each CPU architecture.

GitHub Automation

https://bugzilla.mozilla.org/show_bug.cgi?id=1878868

[github-actions]

🚧 Commit message is using the wrong format: Fix clearDownloadsFolder method for legacy APIs

The comment message should look like:

    Bug xxxx - Short description of your change
    Optionally, a longer description of the change.

[github-actions]

🚧 Commit message is using the wrong format: Fix clearDownloadsFolder method for legacy APIs

The comment message should look like:

    Bug xxxx - Short description of your change
    Optionally, a longer description of the change.

[github-actions]

🚧 Commit message is using the wrong format: Fix clearDownloadsFolder method for legacy APIs

The comment message should look like:

    Bug xxxx - Short description of your change
    Optionally, a longer description of the change.

[github-actions]

🚧 Commit message is using the wrong format: Fix clearDownloadsFolder method for legacy APIs

The comment message should look like:

    Bug xxxx - Short description of your change
    Optionally, a longer description of the change.

[AaronMT]

LGTM, just a comment would be great