PersoSimTest: fixed tests for loading invalid/missing file
personalizations
PersoSim: extracted code into own methods
PersoSimTest: removed indirect method calls via cmd methods
PersoSimTest: removed solved task
Code maintenance

* adjust some comments
* adjust some test method names
Ensure that no unexpected perso is loaded

This change ensures that loading the simulator is aborted if the
indicated perso can not be loaded. This behavior is usefull to ensure
that the user does not operate on a different perso than expected. It
was default behavior up to some commit in the near past and should not
have been changed in the first place.