Non-repository event generators are not handled by `Stand`

[alexander-yevsyukov]

Even though it is possible to subscribe to events generated by a non-repository event producer such as EventReactor, those events are not delivered to the subscriptions. The reason for this is that Stand.registerTypeSupplier() accepts Repository. Other event generators are simply not registered with Stand and therefore information on events they generate is never obtained.

See Stand.messageClasses() which obtains event classes from the EventRegistry. EventRegistry in turn is updated from Stand.registerTypeSupplier().