Gloas cold DB (#8991)

Closes:

- https://github.com/sigp/lighthouse/issues/8958


  - Update the `HotColdStore` to handle storage of cold states.
- Update `BeaconSnapshot` to hold the execution envelope. This is required to make `chain_dump`-related checks sane, and will be generally useful (see: https://github.com/sigp/lighthouse/issues/8956).
- Bug fix in the `BlockReplayer` for the case where the starting state is already `Full` (we should not try to apply another payload). This happens on the cold DB path because we try to replay from the closest cached state (which is often full).
- Update `test_gloas_hot_state_hierarchy` to cover the cold DB migration.


Co-Authored-By: Michael Sproul <michael@sigmaprime.io>

Co-Authored-By: Michael Sproul <michaelsproul@users.noreply.github.com>

beacon_node/beacon_chain/src/beacon_snapshot.rs

@@ -2,7 +2,7 @@ use serde::Serialize;
 use std::sync::Arc;
 use types::{
     AbstractExecPayload, BeaconState, EthSpec, FullPayload, Hash256, SignedBeaconBlock,
-    SignedBlindedBeaconBlock,
+    SignedBlindedBeaconBlock, SignedExecutionPayloadEnvelope,
 };
 
 /// Represents some block and its associated state. Generally, this will be used for tracking the
@@ -10,6 +10,7 @@ use types::{
 #[derive(Clone, Serialize, PartialEq, Debug)]
 pub struct BeaconSnapshot<E: EthSpec, Payload: AbstractExecPayload<E> = FullPayload<E>> {
     pub beacon_block: Arc<SignedBeaconBlock<E, Payload>>,
+    pub execution_envelope: Option<Arc<SignedExecutionPayloadEnvelope<E>>>,
     pub beacon_block_root: Hash256,
     pub beacon_state: BeaconState<E>,
 }
@@ -31,33 +32,42 @@ impl<E: EthSpec, Payload: AbstractExecPayload<E>> BeaconSnapshot<E, Payload> {
     /// Create a new checkpoint.
     pub fn new(
         beacon_block: Arc<SignedBeaconBlock<E, Payload>>,
+        execution_envelope: Option<Arc<SignedExecutionPayloadEnvelope<E>>>,
         beacon_block_root: Hash256,
         beacon_state: BeaconState<E>,
     ) -> Self {
         Self {
             beacon_block,
+            execution_envelope,
             beacon_block_root,
             beacon_state,
         }
     }
 
-    /// Returns the state root from `self.beacon_block`.
+    /// Returns the state root from `self.beacon_block` or `self.execution_envelope` as
+    /// appropriate.
     ///
     /// ## Caution
     ///
     /// It is not strictly enforced that `root(self.beacon_state) == self.beacon_state_root()`.
     pub fn beacon_state_root(&self) -> Hash256 {
-        self.beacon_block.message().state_root()
+        if let Some(ref envelope) = self.execution_envelope {
+            envelope.message.state_root
+        } else {
+            self.beacon_block.message().state_root()
+        }
     }
 
     /// Update all fields of the checkpoint.
     pub fn update(
         &mut self,
         beacon_block: Arc<SignedBeaconBlock<E, Payload>>,
+        execution_envelope: Option<Arc<SignedExecutionPayloadEnvelope<E>>>,
         beacon_block_root: Hash256,
         beacon_state: BeaconState<E>,
     ) {
         self.beacon_block = beacon_block;
+        self.execution_envelope = execution_envelope;
         self.beacon_block_root = beacon_block_root;
         self.beacon_state = beacon_state;
     }