ClusterClient fixes

[Aaronontheweb]

Using the test cases provided by @mwpro on #2535

Also ports:

akka/akka#22992
akka/akka#24167

Close #2535
Close #2312
Close #3840

[Aaronontheweb]

Need to add some copyright headers and wait on MNTR results.

[Aaronontheweb]

Both the uncommented MNTR ClusterClientSpec and the ClusterClientHandoverSpec I ported failed on both .NET Core and .NET Framework - looks like there's still some bugs inside the ClusterClient that these bugs expose - it's the ClusterClient node that fails in all of them.

Attaching the logs from the .NET Core run.

net_core_mntr_windows.zip

[Aaronontheweb]

Have the handover spec working just fine - but the original MNTR ClusterClientSpec had some parts of it that were never implemented or were commented out. Going to take a stab at debugging these before moving on.

[Aaronontheweb]

Looks like there's a hard error:

[Node1:client][FAIL] Akka.Cluster.Tools.Tests.MultiNode.Client.ClusterClientSpec.ClusterClientSpecs
[Node1:client][FAIL-EXCEPTION] Type: Xunit.Sdk.TrueException
--> [Node1:client][FAIL-EXCEPTION] Message: Timeout (00:00:10) during fishForMessage, hint: removal
Expected: True
Actual:   False
--> [Node1:client][FAIL-EXCEPTION] StackTrace:    at Xunit.Assert.True(Nullable`1 condition, String userMessage) in C:\Dev\xunit\xunit\src\xunit.assert\Asserts\BooleanAsserts.cs:line 95
   at Akka.TestKit.TestKitBase.FishForMessage[T](Predicate`1 isMessage, Nullable`1 max, String hint) in D:\a\1\s\src\core\Akka.TestKit\TestKitBase_Receive.cs:line 52
   at Akka.Cluster.Tools.Tests.MultiNode.Client.ClusterClientSpec.<ClusterClient_must_report_removal_of_a_receptionist>b__18_1() in D:\a\1\s\src\contrib\cluster\Akka.Cluster.Tools.Tests.MultiNode\ClusterClient\ClusterClientSpec.cs:line 518
   at Akka.Cluster.Tools.Tests.MultiNode.Client.ClusterClientSpec.<ClusterClient_must_report_removal_of_a_receptionist>b__18_0() in D:\a\1\s\src\contrib\cluster\Akka.Cluster.Tools.Tests.MultiNode\ClusterClient\ClusterClientSpec.cs:line 520
   at Akka.TestKit.TestKitBase.<>c__DisplayClass141_0.<Within>b__0() in D:\a\1\s\src\core\Akka.TestKit\TestKitBase_Within.cs:line 48
   at Akka.TestKit.TestKitBase.Within[T](TimeSpan min, TimeSpan max, Func`1 function, String hint, Nullable`1 epsilonValue) in D:\a\1\s\src\core\Akka.TestKit\TestKitBase_Within.cs:line 101
   at Akka.TestKit.TestKitBase.Within(TimeSpan min, TimeSpan max, Action action, String hint, Nullable`1 epsilonValue) in D:\a\1\s\src\core\Akka.TestKit\TestKitBase_Within.cs:line 49
   at Akka.TestKit.TestKitBase.Within(TimeSpan max, Action action, Nullable`1 epsilonValue) in D:\a\1\s\src\core\Akka.TestKit\TestKitBase_Within.cs:line 32
   at Akka.Cluster.Tools.Tests.MultiNode.Client.ClusterClientSpec.ClusterClient_must_report_removal_of_a_receptionist() in D:\a\1\s\src\contrib\cluster\Akka.Cluster.Tools.Tests.MultiNode\ClusterClient\ClusterClientSpec.cs:line 522
   at Akka.Cluster.Tools.Tests.MultiNode.Client.ClusterClientSpec.ClusterClientSpecs() in D:\a\1\s\src\contrib\cluster\Akka.Cluster.Tools.Tests.MultiNode\ClusterClient\ClusterClientSpec.cs:line 290

Going to see if it's an issue with the way I ported those assertions.

[Aaronontheweb]

Now have the ClusterClientSpec mostly working end to end - have one issue in the final set of assertions that I need to debug but otherwise this PR is good to go.

[Aaronontheweb]

Should resolve this issue too #2312

[Aaronontheweb]

MNTR failed on an unrelated DistributedPubSub spec, but I know what the root cause of that is. Documented it here: #3868