records hash of timed-out pull responses

Gossip should record hash of pull responses which are timed out and
fail to insert:
https://github.com/solana-labs/solana/blob/ed51cde37/core/src/crds_gossip_pull.rs#L397-L400

so that they are excluded from the next pull request:
https://github.com/solana-labs/solana/blob/ed51cde37/core/src/crds_gossip_pull.rs#L486-L491

otherwise the next pull request will likely include the same timed out
values and waste bandwidth.

core/src/crds_gossip_pull.rs

@@ -367,37 +367,38 @@ impl CrdsGossipPull {
     ) -> (Vec<CrdsValue>, Vec<CrdsValue>, Vec<Hash>) {
         let mut active_values = vec![];
         let mut expired_values = vec![];
-        let mut failed_inserts = vec![];
-        let mut maybe_push = |response, values: &mut Vec<CrdsValue>| {
-            if crds.upserts(&response) {
-                values.push(response);
-            } else {
-                let response = bincode::serialize(&response).unwrap();
-                failed_inserts.push(hash(&response));
-            }
-        };
         let default_timeout = timeouts
             .get(&Pubkey::default())
             .copied()
             .unwrap_or(self.msg_timeout);
-        for response in responses {
+        let upsert = |response: CrdsValue| {
             let owner = response.label().pubkey();
             // Check if the crds value is older than the msg_timeout
             let timeout = timeouts.get(&owner).copied().unwrap_or(default_timeout);
             // Before discarding this value, check if a ContactInfo for the
             // owner exists in the table. If it doesn't, that implies that this
             // value can be discarded
-            if now <= response.wallclock().saturating_add(timeout) {
-                maybe_push(response, &mut active_values);
+            if !crds.upserts(&response) {
+                Some(response)
+            } else if now <= response.wallclock().saturating_add(timeout) {
+                active_values.push(response);
+                None
             } else if crds.get_contact_info(owner).is_some() {
                 // Silently insert this old value without bumping record
                 // timestamps
-                maybe_push(response, &mut expired_values);
+                expired_values.push(response);
+                None
             } else {
                 stats.timeout_count += 1;
                 stats.failed_timeout += 1;
+                Some(response)
             }
-        }
+        };
+        let failed_inserts = responses
+            .into_iter()
+            .filter_map(upsert)
+            .map(|resp| hash(&bincode::serialize(&resp).unwrap()))
+            .collect();
         (active_values, expired_values, failed_inserts)
     }
 
@@ -1529,7 +1530,7 @@ mod test {
                 node.msg_timeout + 100,
             )
             .0,
-            2
+            4
         );
 
         let mut node_crds = Crds::default();
@@ -1574,7 +1575,7 @@ mod test {
                 node.msg_timeout + 2,
             )
             .0,
-            1
+            2
         );
     }
 }