Changes related to old unit tests

Here I basically rewrote the code that runs unit tests for old unit test logfiles, as part of the regressions suite. It's more logical to have all that together with the regressions, and not defined in the unit tests. The only place of contact between the two is when the regression suite borrows unit tests classes in order to run them on the old unit test logfiles.

I hope this way the upkeep of old unit tests will be easier. It's not all done, but the bulk of it is. Some more exceptions for the old unit tests are needed, and some things need to be moved to the unit tests, I think.

But I am pushing what I have for now.