Currently, the broker will lose messages in the following scenario:
1. Client creates receiver to a queue (queue has an alternate exchange configured)
2. Client acquires message from queue
3. Client closes receiver (with delete:always or delete:receiver)
4. Client closes session
We expect that the messages should be sent to the now-deleted queue's alternate exchange if/when they are released.
Messages are not sent to the alternate exchange immediately upon closure of the receiver because the client still has acquired messages; this is fine, but when the client either releases the messages or closes the session, these messages should be sent to the alternate exchange.