fix: ref_index_calib* tests

@jonrob this should make the nightly tests for Panoptes green again.

I've removed the multithreading as the algorithms aren't thread safe.
I don't think the diff of the test looks too concerning, but I'd appreciate if you could have a quick look at those :)

Note that the tests as they have been configured only check the last calibration run which is performed in the finalize() call.
All the other printouts aren't used for the validation, which is a bit of a shame.
I tried changing that, but for some reason that made the tests fail occasionally again.
This seems to be mostly caused by the cameraTool which for whatever reason doesn't have the printouts at the same location... 🤷
I don't really have the time to dig into that right now, but figured this first step at least gets the test green and allows us to have some kind of test coverage again in Panoptes.

somewhat closes #1 (closed)