Clean up temporary home directory to make tests more robust (backport #3146)

[mergify]

🦟 Bug fix

Fixes #3031

Summary

I think I know what the issue is with the UtilTest.ResolveSdfWorldFile test. It appears that the temporary directory created for Fuel caches in the tests are not cleared properly. It's also not clear if these are being created on in-memory file system on macOS, which means they persist across reboots.

• As a result of this, the test is not running properly. It is not downloading the test world every time. Instead, it's using cached files which might be corrupt.
• I reproduced a similar test failure by going into the cache location and only removing the test.sdf file.

This patch cleans up the temporary home directory when each test is done.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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This is an automatic backport of pull request #3146 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 83a6331 has failed:

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Changes to be committed:
	modified:   test/helpers/EnvTestFixture.hh

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   test/integration/log_system.cc

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally