banking_stage: use iproduct! macro in test

core/src/banking_stage/unprocessed_transaction_storage.rs

@@ -1017,6 +1017,7 @@ impl ThreadLocalUnprocessedPackets {
 mod tests {
     use {
         super::*,
+        itertools::iproduct,
         solana_ledger::genesis_utils::{create_genesis_config, GenesisConfigInfo},
         solana_perf::packet::{Packet, PacketFlags},
         solana_runtime::genesis_utils,
@@ -1273,10 +1274,10 @@ mod tests {
             assert!(deserialized_packets.contains(&big_transfer));
         }
 
-        for (vote_source, staked) in [VoteSource::Gossip, VoteSource::Tpu]
-            .into_iter()
-            .flat_map(|vs| [(vs, true), (vs, false)])
-        {
+        for (vote_source, staked) in iproduct!(
+            [VoteSource::Gossip, VoteSource::Tpu].into_iter(),
+            [true, false].into_iter()
+        ) {
             let latest_unprocessed_votes = LatestUnprocessedVotes::default();
             if staked {
                 latest_unprocessed_votes.set_staked_nodes(&[keypair.pubkey()]);