Failing DurableTask.ServiceBus tests

These two tests currently fail due to asserts that fire during test execution:

* OrchestrationHubTableClientTests.TerminateInstanceStoreTest
* ServiceBusOrchestrationServiceTests.ActorOrchestrationTest

```
---------------------------
Assertion Failed: Abort=Quit, Retry=Debug, Ignore=Continue
---------------------------
at DurableTask.Core.OrchestrationRuntimeState.get_OrchestrationStatus() in C:\GitHub\durabletask\src\DurableTask.Core\OrchestrationRuntimeState.cs:line 161
at DurableTask.ServiceBus.ServiceBusOrchestrationService.d__98.MoveNext() in C:\GitHub\durabletask\src\DurableTask.ServiceBus\ServiceBusOrchestrationService.cs:line 1535
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start[TStateMachine](TStateMachine& stateMachine)
at DurableTask.ServiceBus.ServiceBusOrchestrationService.TrySetSessionStateAsync(TaskOrchestrationWorkItem workItem, OrchestrationRuntimeState newOrchestrationRuntimeState, OrchestrationRuntimeState runtimeState, MessageSession session)
at DurableTask.ServiceBus.ServiceBusOrchestrationService.d__63.MoveNext() in C:\GitHub\durabletask\src\DurableTask.ServiceBus\ServiceBusOrchestrationService.cs:line 662
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[TStateMachine](TStateMachine& stateMachine)
at DurableTask.ServiceBus.ServiceBusOrchestrationService.CompleteTaskOrchestrationWorkItemAsync(TaskOrchestrationWorkItem workItem, OrchestrationRuntimeState newOrchestrationRuntimeState, IList`1 outboundMessages, IList`1 orchestratorMessages, IList`1 timerMessages, TaskMessage continuedAsNewMessage, OrchestrationState orchestrationState)
at DurableTask.Core.TaskOrchestrationDispatcher.d__20.MoveNext() in C:\GitHub\durabletask\src\DurableTask.Core\TaskOrchestrationDispatcher.cs:line 418
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start[TStateMachine](TStateMachine& stateMachine)
at DurableTask.Core.TaskOrchestrationDispatcher.OnProcessWorkItemAsync(TaskOrchestrationWorkItem workItem)
at DurableTask.Core.TaskOrchestrationDispatcher.d__19.MoveNext() in C:\GitHub\durabletask\src\DurableTask.Core\TaskOrchestrationDispatcher.cs:line 116
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[TStateMachine](TStateMachine& stateMachine)
at DurableTask.Core.TaskOrchestrationDispatcher.OnProcessWorkItemSessionAsync(TaskOrchestrationWorkItem workItem)
at DurableTask.Core.WorkItemDispatcher`1.d__39.MoveNext() in C:\GitHub\durabletask\src\DurableTask.Core\WorkItemDispatcher.cs:line 309
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[TStateMachine](TStateMachine& stateMachine)
at DurableTask.Core.WorkItemDispatcher`1.ProcessWorkItemAsync(WorkItemDispatcherContext context, Object workItemObj)
at DurableTask.Core.WorkItemDispatcher`1.<>c__DisplayClass38_1.b__0() in C:\GitHub\durabletask\src\DurableTask.Core\WorkItemDispatcher.cs:line 274
at System.Threading.Tasks.Task`1.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
at System.Threading.Tasks.Task.ExecutionContextCallback(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext,ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
at System.Threading.Tasks.Task.ExecuteEntry(Boolean bPreventDoubleExecution)
at System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

---------------------------
Abort Retry Ignore
---------------------------
```

Ignoring the assert causes the tests to pass.

Führe zunächst OrchestrationHubTableClientTests.TerminateInstanceStoreTest und ServiceBusOrchestrationServiceTests.ActorOrchestrationTest aus. Lies OrchestrationRuntimeState.cs etwa ab Zeile 161 und ServiceBusOrchestrationService.cs etwa ab Zeile 1535 und folge dabei dem Assertion-Stack. Die Aufgabe ist abgeschlossen, wenn beide Tests bestehen, ohne dass der Assertion-Dialog ignoriert werden muss.

Vom Indexierungsmodell aus dem Issue-Text verfasst.