MacOS tests often time out

[joernu76]

I notice that the macos tests often (say >20% for sure) time out after 40 minutes. This is highly annoying.
Maybe allow them to fail?
For gitlab we have a https://github.com/testmoapp/junitxml based test reporting to the server, where we can analyse failed tests and see there individual execution time. I would assume that this will not generate results in a time out, but maybe one could gain some simpler insight from non-failed runs into bottlenecks?

[ReimarBauer]

This seems now better, we don't run in test timeout but in the RuntimeError: Server did not start #2967 often on MacOS

[ReimarBauer]

we reduced the timeouts by #2969

there are still some problems also in the ubuntu test.