Fix failing Windows and macOS tests

[msimberg]

We do not currently have perfect test runs on Windows and macOS. Tests that we know fail have been added to blacklists in the GitHub actions workflow files (Windows and macOS).

We would appreciate help from people working on those platforms to determine if the fault lies in the test environment or if the test failures are reproducible in other environments too.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.