Cross node supervised task can hang forever

This PR is not intended for inclusion but is an attempt at showing a race condition when spawning a supervised task on another node.

Conditions:
* A cross node `Task.Sup.async` call is made while the supervisor is busy spawning previous tasks
* The nodes disconnect
* The call fails and is caught, the calling process does not exit
* The task is spawned and links to the calling process, causing the nodes to reconnect
* The calling process has not exited and so does not send its monitor reference
* The spawned task waits forever for the monitor reference so it can begin