This adds a timeout of 60 minutes for the Cppcheck analysis.
Timed out results do not count as crash but they are uploaded and
marked with "TO!" in the list of the latest results. No "diff" is
generated for timed out results so they do not add wrong entries to
the "Diff report".
In test-my-pr.py the timed out results are listed separately just like
the crashes.
donate-cpu-server.py: Add timeout report
Previously, calling test-my-pr with a relative work-path resulted in a
crash when trying to create the result file (due to the change of
current working directory).