refs https://github.com/TryGhost/Toolbox/issues/138
- There is no good reason to keep this extra variable around just call "stop" in couple very specific cases. Even for those cases, there's `testUtils.stopGhost` method which achieves the same without additional variable to track.
refs https://github.com/TryGhost/Toolbox/issues/138
- Having the "ghost" alias only added cognitive load when reading through the test code and didn't provide any additional value. Removed the pattern to keep things simpler and more explicit