As reported in zfcampus#18, a circular dependency lookup can occur when
specifying a static method of a class as a `callable` for an RPC service
that matches the class name for the RPC service. As an example:

```php
return [
    'zf-rpc' => [
        SomeController::class => [
            'callable' => SomeController::class . '::bar',
        ],
    ],
];
```

In the above case, the `RpcControllerFactory` would be invoked for
`SomeController::class`, find the `callable` entry of
`{NS}\SomeController::bar`, split this into the class and method, and
then attempt to fetch `SomeController::class` again, ad infinitum.

This patch adds a private property, `$lastRequestedControllerService`,
which is set to the service being pulled whenever we attempt to marshal
a service from the controller manager. If a subsequent invocation finds
that the service requested matches that property value, then we do not
attempt to pull from the controller manager again, but move on to the
parent container (if we have one), or directly instantiating the class.
(The `$lastRequestedControllerService` is reset otherwise.)

Fixes zfcampus#18