Add structure to collect and coalesce vote packets (#27558)

* Add structure to collect and coalesce vote packets

Will be used in banking stage to throw out extraneous vote packets
before processing

* pr comments

* Update inner lock to arc to improve performance

Author: AshwinSekar

core/src/forward_packet_batches_by_accounts.rs

@@ -99,7 +99,7 @@ impl ForwardBatch {
 pub struct ForwardPacketBatchesByAccounts {
     // Need a `bank` to load all accounts for VersionedTransaction. Currently
     // using current rooted bank for it.
-    current_bank: Arc<Bank>,
+    pub(crate) current_bank: Arc<Bank>,
     // Forwardable packets are staged in number of batches, each batch is limited
     // by cost_tracker on both account limit and block limits. Those limits are
     // set as `limit_ratio` of regular block limits to facilitate quicker iteration.

core/src/immutable_deserialized_packet.rs

@@ -28,6 +28,8 @@ pub enum DeserializedPacketError {
     SanitizeError(#[from] SanitizeError),
     #[error("transaction failed prioritization")]
     PrioritizationFailure,
+    #[error("vote transaction failure")]
+    VoteTransactionError,
 }
 
 #[derive(Debug, PartialEq, Eq)]