Support for custom BroadcastStage in local cluster tests (#4716)

* Refactor BroadcastStage to support custom implementations, add FailEntryVerificationBroadcastRun implementation

* Plumb switch on broadcast type through validator

* Add test for validator generating non-verifiable entries to local_cluster

* Fix bad initializers

* Refactor broadcast run code into utils

bench-tps/src/bench.rs

@@ -668,12 +668,11 @@ mod tests {
     #[test]
     fn test_bench_tps_local_cluster() {
         solana_logger::setup();
-        let validator_config = ValidatorConfig::default();
         const NUM_NODES: usize = 1;
         let cluster = LocalCluster::new(&ClusterConfig {
             node_stakes: vec![999_990; NUM_NODES],
             cluster_lamports: 2_000_000,
-            validator_config,
+            validator_configs: vec![ValidatorConfig::default(); NUM_NODES],
             ..ClusterConfig::default()
         });