This change ensures that setting ExceptionContext.Result will always
execute if set. The problem with 1.1.0 is that when we had a real short
circuit the wrong set of conditions were checked. I suspect that when you
set ExceptionFilter.Result and didn't short circuit that result filters
were also running (which is a bug).
Added a few tests that verify that the result doesn't trigger result
filters.
I did some general cleanup on this code path to make the state transitions
more clear.
No exception was thrown -> BeginResult
Exception was handled -> ExceptionHandled
Exception was not handled -> gets rethrown
