[Merge] Optimistic Sync: Stage 1 (#2686)

* Add payload verification status to fork choice

* Pass payload verification status to import_block

* Add valid back-propagation

* Add head safety status latch to API

* Remove ExecutionLayerStatus

* Add execution info to client notifier

* Update notifier logs

* Change use of "hash" to refer to beacon block

* Shutdown on invalid finalized block

* Tidy, add comments

* Fix failing FC tests

* Allow blocks with unsafe head

* Fix forkchoiceUpdate call on startup

beacon_node/beacon_chain/src/fork_revert.rs

@@ -1,5 +1,5 @@
 use crate::{BeaconForkChoiceStore, BeaconSnapshot};
-use fork_choice::ForkChoice;
+use fork_choice::{ForkChoice, PayloadVerificationStatus};
 use itertools::process_results;
 use slog::{info, warn, Logger};
 use state_processing::state_advance::complete_state_advance;
@@ -164,9 +164,21 @@ pub fn reset_fork_choice_to_finalization<E: EthSpec, Hot: ItemStore<E>, Cold: It
         )
         .map_err(|e| format!("Error replaying block: {:?}", e))?;
 
+        // Setting this to unverified is the safest solution, since we don't have a way to
+        // retro-actively determine if they were valid or not.
+        //
+        // This scenario is so rare that it seems OK to double-verify some blocks.
+        let payload_verification_status = PayloadVerificationStatus::NotVerified;
+
         let (block, _) = block.deconstruct();
         fork_choice
-            .on_block(block.slot(), &block, block.canonical_root(), &state)
+            .on_block(
+                block.slot(),
+                &block,
+                block.canonical_root(),
+                &state,
+                payload_verification_status,
+            )
             .map_err(|e| format!("Error applying replayed block to fork choice: {:?}", e))?;
     }