Step hooks were not firing when you did a "step out".
This was because, when a breakpoint's PerformAction observes that the breakpoint has completed a plan, it resets the thread StopInfo so that the completed plan will be reported as the stop reason, not the trap that is the private stop reason. But for no good reason that I can remember, it doesn't immediately reset the StopInfo to the completed plan one, but lets that happen the next time somebody gets the stop reason. That didn't happen by the time stop-hooks checked if the thread had a stop reason.
We could make the stop-hooks force the StopInfo to get recomputed, but that might happen somewhere else as well. It's better to just do it right away.
I also added a test for this case.