When the endpoint reconcilers got split out of pkg/controlplane,
GetMasterServiceUpdateIfNeeded() got moved to
pkg/controlplane/reconcilers, even though it needs to be kept in sync
with CreateOrUpdateMasterServiceIfNeeded() which stayed in
pkg/controlplane. (And everything else in pkg/controlplane/reconcilers
is about the Endpoints not the Service anyway.) So move it back.
On the flip side, the implementation of masterCountEndpointReconciler
got moved to pkg/controlplane/reconcilers, but its unit tests didn't.
So belatedly fix that.