Fix unit test failures on recent macOS ARM platforms

As discussed [on Slack](https://opencolorio.slack.com/archives/C3Q43TN4Q/p1706842156429159), several people have reported that the CPU and GPU unit tests fail on macOS ARM chips with macOS 14.

Our experiments to set up a macOS ARM CI runner (also macOS 14) [ran into similar problems.](https://github.com/AcademySoftwareFoundation/OpenColorIO/actions/runs/7677346079)

It looks like many of the failures are probably ok but just slightly outside the existing tolerances or are happening where there currently are no tolerances in the test but should be.

This task will require going through the failing tests one by one and deciding what to do. If you want to take this on, please reach out on Slack and run into questions about a given test.

Inizia riproducendo i fallimenti degli unit test di CPU e GPU in un ambiente macOS 14 ARM e verifica la run CI macOS ARM indicata. Esamina ogni test che fallisce, decidendo se sia necessario modificare la relativa tolleranza o aggiungere una tolleranza mancante; il lavoro è completato quando i test interessati passano senza mascherare fallimenti autentici.

Scritto dal modello di indicizzazione a partire dal testo della issue.