Fix racy FunctionRefSpecs

[Aaronontheweb]

Changes

Noticed that these were failing racily on #7168 - I'm able to reproduce the failure in Rider using "run until failure" pretty easily. Working on debugging these.

Checklist

For significant changes, please ensure that the following have been completed (delete if not relevant):

• This change follows the Akka.NET API Compatibility Guidelines.
• This change follows the Akka.NET Wire Compatibility Guidelines.
• I have reviewed my own pull request.

[Aaronontheweb]

I see this method time out - working on figuring out why. The other two calls below can also time out.

[Aaronontheweb]

FunctionRef_created_by_top_level_actor_must_be_watchable

Failed: Expected a message of type Akka.Actor.Terminated, but received {[akka://FunctionRefSpec-7/user/super/$$b#224401843]} (type Akka.Actor.Function...

Xunit.Sdk.FailException
Failed: Expected a message of type Akka.Actor.Terminated, but received {[akka://FunctionRefSpec-7/user/super/$$b#224401843]} (type Akka.Actor.FunctionRef) instead Terminated [akka://FunctionRefSpec-7/user/super/$$a#1445975092].  from [akka://FunctionRefSpec-7/user/super#791687691]
   at Akka.TestKit.Xunit2.XunitAssertions.Fail(String format, Object[] args) in E:\Repositories\olympus\akka.net\src\contrib\testkits\Akka.TestKit.Xunit2\XunitAssertions.cs:line 26
   at Akka.TestKit.TestKitBase.<InternalExpectMsgEnvelopeAsync>d__140`1.MoveNext() in E:\Repositories\olympus\akka.net\src\core\Akka.TestKit\TestKitBase_Expect.cs:line 445
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at Akka.TestKit.TestKitBase.<InternalExpectMsgEnvelopeAsync>d__139`1.MoveNext() in E:\Repositories\olympus\akka.net\src\core\Akka.TestKit\TestKitBase_Expect.cs:line 411
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at Akka.TestKit.TestKitBase.<InternalExpectMsgAsync>d__137`1.MoveNext() in E:\Repositories\olympus\akka.net\src\core\Akka.TestKit\TestKitBase_Expect.cs:line 379
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at Akka.Tests.Actor.FunctionRefSpec.<FunctionRef_created_by_top_level_actor_must_be_watchable>d__8.MoveNext() in E:\Repositories\olympus\akka.net\src\core\Akka.Tests\Actor\FunctionRefSpecs.cs:line 160
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Xunit.Sdk.TestInvoker`1.<>c__DisplayClass48_0.<<InvokeTestMethodAsync>b__1>d.MoveNext() in /_/src/xunit.execution/Sdk/Frameworks/Runners/TestInvoker.cs:line 276
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Xunit.Sdk.ExecutionTimer.<AggregateAsync>d__4.MoveNext() in /_/src/xunit.execution/Sdk/Frameworks/ExecutionTimer.cs:line 48
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Xunit.Sdk.ExceptionAggregator.<RunAsync>d__9.MoveNext() in /_/src/xunit.core/Sdk/ExceptionAggregator.cs:line 90



[INFO][04/24/2024 12:15:54.741Z][Thread 0022][ActorSystem(FunctionRefSpec-7)] Starting FunctionRefSpec
[DEBUG][04/24/2024 12:15:54.743Z][Thread 0024][akka://FunctionRefSpec-7/user/super] received handled message Akka.Tests.Actor.FunctionRefSpec+GetForwarder from akka://FunctionRefSpec-7/system/testActor7
[DEBUG][04/24/2024 12:15:54.743Z][Thread 0024][akka://FunctionRefSpec-7/user/super] received handled message Akka.Tests.Actor.FunctionRefSpec+GetForwarder from akka://FunctionRefSpec-7/system/testActor7
[DEBUG][04/24/2024 12:15:54.743Z][Thread 0018][akka://FunctionRefSpec-7/user/super] received handled message Akka.Tests.Actor.FunctionRefSpec+DropForwarder from akka://FunctionRefSpec-7/system/testActor7
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0024][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [before-service-unbind] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [service-unbind] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [service-requests-done] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [service-stop] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [before-cluster-shutdown] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [cluster-sharding-shutdown-region] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [cluster-leave] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [cluster-exiting] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [cluster-exiting-done] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [cluster-shutdown] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [before-actor-system-terminate] with [0] tasks.
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][CoordinatedShutdown (akka://FunctionRefSpec-7)] Performing phase [actor-system-terminate] with [1] tasks: [terminate-system]
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0016][ActorSystem(FunctionRefSpec-7)] System shutdown initiated
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0022][EventStream] Shutting down: StandardOutLogger started
[DEBUG][04/24/2024 12:15:54.745Z][Thread 0022][EventStream] All default loggers stopped

[Aaronontheweb]

Welp, this was dumb - old bug in the test suite that got "fixed" when I made sure that Watch / Unwatch worked properly in the TestKit.

[Aaronontheweb]

Detailed my changes