caches vote-state de-serialized from vote accounts (#13795)

Gossip and other places repeatedly de-serialize vote-state stored in
vote accounts. Ideally the first de-serialization should cache the
result.

This commit adds new VoteAccount type which lazily de-serializes
VoteState from Account data and caches the result internally.

Serialize and Deserialize traits are manually implemented to match
existing code. So, despite changes to frozen_abi, this commit should be
backward compatible.

runtime/src/serde_snapshot/tests.rs

@@ -261,7 +261,7 @@ mod test_bank_serialize {
 
     // These some what long test harness is required to freeze the ABI of
     // Bank's serialization due to versioned nature
-    #[frozen_abi(digest = "Giao4XJq9QgW78sqmT3nRMvENt4BgHXdzphCDGFPbXqW")]
+    #[frozen_abi(digest = "8bNY87hccyDYCRar1gM3NSvpvtiUM3W3rGeJLJayz42e")]
     #[derive(Serialize, AbiExample)]
     pub struct BankAbiTestWrapperFuture {
         #[serde(serialize_with = "wrapper_future")]