Use file servers in LearningTest

[bruno-at-orange]

We added the possibility to simulate the execution of Khiops on multi-machines by launching a file server process on a single host. The file server is launched when the environment variable KhiopsFileServerActivated is set to true.

It would be a good thing to use this feature on LearningTest, on CI. I launch LearningTest on the full family on my laptop. the good news is there is no bugs. However, there are multiples warnings and errors. We have to correct these errors before using file servers on LearningTest.

The errors are mainly in the crash tests, results files are here

[marcboulle]

Après analyse rapide des résultats, le problème suivant est facile à gérer:

• TestKhiops/SideEffects/BugMissingSparseData: il manquait juste le fichier time.log dans les résultats de référence

Sinon, il semble qu'il y ait quand même une erreurs liée au reporting des erreurs systèmes dans certaines jeux de tests. Exemple: TestKhiops/CrashTests/extractkeys_KWFileKeyExtractorTask

• "Unable to read file (operation canceled)" dans results.ref
• "Unable to read file (Success)" dans results: le "Success" semble un bug de reporting

Les autres variations semblent "normales": à vérifier

[bruno-at-orange]

After the fixes in #608 there is no more issues when using the file servers.