refactoring; update shell Fork-Bomb test which can fail in different ways
refactoring; update shell Fork-Bomb test which can fail in different ways

cyber-dojo/runner,cyber-dojo/runner_stateless,cyber-dojo/runner_stateless,cyber-dojo/runner_stateless,cyber-dojo/runner_stateless,cyber-dojo/runner,cyber-dojo/runner_stateless,cyber-dojo/runner_stateless,cyber-dojo/runner_stateless