[Outreachy] Microproject idea: modernize a file-existence check in t/t0081-find-pack.sh

Hi,

I'm preparing a microproject contribution for Outreachy and have been exploring a small test cleanup in Git.

In t/t0081-find-pack.sh, line 35 currently uses:

test -f "$head_commit_pack" &&

I'm considering replacing it with Git's test helper:

test_path_is_file "$head_commit_pack" &&

I checked the file's history using git blame and confirmed that this is the only test -f, test -e, or test -d check in that script.

Would this be an appropriate and useful microproject, or is there a reason to leave this check as it is?

I have cloned Git, built it with NO_RUST=1, and run the test suite. I have not made any changes to the source yet.

Thank you for your time.