Create bank snapshots (#4244)

* Revert "Revert "Create bank snapshots (#3671)" (#4243)"

This reverts commit 81fa69d347.

* keep saved and unsaved copies of status cache

* fix format check

* bench for status cache serialize

* misc cleanup

* remove appendvec storage on purge

* fix accounts restore

* cleanup

* Pass snapshot path as args

* Fix clippy

core/tests/cluster_info.rs

@@ -1,9 +1,9 @@
-use hashbrown::{HashMap, HashSet};
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use rayon::prelude::*;
 use solana::cluster_info::{compute_retransmit_peers, ClusterInfo};
 use solana::contact_info::ContactInfo;
 use solana_sdk::pubkey::Pubkey;
+use std::collections::{HashMap, HashSet};
 use std::sync::mpsc::channel;
 use std::sync::mpsc::TryRecvError;
 use std::sync::mpsc::{Receiver, Sender};

core/tests/crds_gossip.rs

@@ -1,5 +1,4 @@
 use bincode::serialized_size;
-use hashbrown::HashMap;
 use log::*;
 use rayon::prelude::*;
 use solana::contact_info::ContactInfo;
@@ -11,6 +10,7 @@ use solana::crds_value::CrdsValueLabel;
 use solana_sdk::hash::hash;
 use solana_sdk::pubkey::Pubkey;
 use solana_sdk::timing::timestamp;
+use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
 
 type Node = Arc<Mutex<CrdsGossip>>;

core/tests/tvu.rs

@@ -94,7 +94,7 @@ fn test_replay() {
         completed_slots_receiver,
         leader_schedule_cache,
         _,
-    ) = validator::new_banks_from_blocktree(&blocktree_path, None);
+    ) = validator::new_banks_from_blocktree(&blocktree_path, None, None);
     let working_bank = bank_forks.working_bank();
     assert_eq!(
         working_bank.get_balance(&mint_keypair.pubkey()),