Increase timeouts in processor tests

For some reason, these constantly failed for me while waiting for the key pair
to confirm. This adds a sleep during the mining process, to ensure blocks
actually have time between them, and mines several more blocks to handle the
median code recently added.

tests/processor/src/lib.rs

@@ -233,7 +233,7 @@ impl Coordinator {
   /// Receive a message from a processor as its coordinator.
   pub async fn recv_message(&mut self) -> ProcessorMessage {
     let msg = tokio::time::timeout(
-      core::time::Duration::from_secs(10),
+      core::time::Duration::from_secs(20),
       self.queue.next(Service::Processor(self.network)),
     )
     .await