Bug: keep cache state after last scenario

[erickloss]

currently, due to ContentCache:shutdownObject() on test-runner flow termination, the tags for node fixtures that were created in the scenario gets flushed. That leaves the SuT in a different state of what the scenario created via fixtures and SuT calls. This makes debugging cache bugs with tests nearly impossible without exiting the PHP process manually (die/exit in the last step).

Idea:
prevent tag cache flush explicitly after the scenario execution