Clean up FileGitAlgTest

[fthomas]

This

• removes .unsafeRunSync from FileGitAlgTest
• renames Supplement to AuxGitAlg

[codecov]

Codecov Report

Merging #2268 (7bc22cc) into master (5fea5f1) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2268   +/-   ##
=======================================
  Coverage   77.91%   77.91%           
=======================================
  Files         135      135           
  Lines        2291     2291           
  Branches       60       60           
=======================================
  Hits         1785     1785           
  Misses        506      506           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5fea5f1...7bc22cc. Read the comment docs.