Run automated tests on Mac/Windows

[hinerm]

Currently the tests just work on Linux.

Changes needed/known issues for Mac/Linux:

• The jaunch.t tests use the configurator directly so would need a platform-agnostic version to use
• Mac tests are full of "+ Ignoring 1 trailing output lines." errors when matching globs (curious if this is happens when not using the wrapper script)
• The python installed by actions/setup-python@v5 isn't detected on Mac
• prysk installs on Windows but fails with shell not found: /bin/sh. cram "passes" but doesn't actually run the tests.

[ctrueden]

With 25f0b0d, the tests now run on the macOS CI node, and with the next couple of commits after that, the tests are passing on macOS CI. All that remains for this issue is to make them fully work on Windows—although #74 may need to be resolved in tandem.