[#1726]  Wait a lot for group creation.


Problem description
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Even if we create a group on Unix on some version of Linux the group is visible in one function call and not in another.



Changes description
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Use  2 methods of checking that group is visible to Python.

For getting the group by name we wait for up to 30 seconds.

I went with remote debugger and I have no idea what is wrong there.

With the new changes we should see errors in setUp rather than in the test.


How to try and test the changes
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reviewers @alibotean 

In case we still see errors we will increase the timeout.

Thanks!