Remove #define private public from all tests

[dkroenke]

Required information

In some of the iceoryx tests are defines used for making private=public which is against our principle of white-box testing.
Additionally this doesn't compile on windows.

Task

• remove #define private public and #define protected public from all testfiles
  • test_gw_gateway_discovery.cpp (part of #Iox #190 fixed point types for duration internal representation #501)
  • test_roudi_service_registry.cpp (trivial)
  • test_objectpool.cpp (easy by making protected accessor methods; the objectpool might be removed in the future though)
  • test_mq_interface.cpp (intermediate; mq_interface will be refactored in the near future though)
  • test_posh_mepoo.cpp (non-trivial and probably difficult)

[elBoberido]

oh, I also added it to the Windows Issue.
Nevertheless, test_gw_gateway_discovery.cpp will be fixed with the Duration PR

[dkroenke]

@elBoberido yes right, this is for the new contributors to get familiar.

[elBoberido]

@dkroenke I had a look at it yesterday and at least one is not quite trivial to solve. Shall I tag the files from easy to difficult?

[dkroenke]

@elBoberido Yes that definitely make sense

[elBoberido]

@dkroenke done. I think mq_interface will be refactored in the near future and should maybe be done with that refactoring