be explicit of test expects zero transaction fee (solana-labs#34846)

be explcit of test expects 0 transaction fee

runtime/src/snapshot_bank_utils.rs

@@ -1761,7 +1761,9 @@ mod tests {
         let incremental_snapshot_archives_dir = tempfile::TempDir::new().unwrap();
         let snapshot_archive_format = ArchiveFormat::Tar;
 
-        let (genesis_config, mint_keypair) = create_genesis_config(sol_to_lamports(1_000_000.));
+        let (mut genesis_config, mint_keypair) = create_genesis_config(sol_to_lamports(1_000_000.));
+        // test expects 0 transaction fee
+        genesis_config.fee_rate_governor = solana_sdk::fee_calculator::FeeRateGovernor::new(0, 0);
 
         let lamports_to_transfer = sol_to_lamports(123_456.);
         let (bank0, bank_forks) = Bank::new_with_paths_for_tests(