Examine/solve suspected data bug

[pflanze]

There appears to be a bug with the data? At least we couldn't make sense of some of the numbers, thus have to go through it. Also see if can add end to end tests (generate a log file, see if getting expected data out).

[pflanze]

Decided on 26 Aug that I just study and document first, there may be no bug; collect evidence of possible bug (sadly we didn't take note of the details) before doing the remaining bulk of the testing work.

[pflanze]

Once evobench-evaluator (and -probes) documentation is done and no issue was seen, this can be closed, as we haven't noticed any issues again so far.

Also of note is f110a8c which creates separate avg and sum "summaries", the missing distinction of which was part of the confusion.