[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

consensus/fork_choice/tests/tests.rs

@@ -10,7 +10,10 @@ use beacon_chain::{
     BeaconChain, BeaconChainError, BeaconForkChoiceStore, ChainConfig, ForkChoiceError,
     StateSkipConfig, WhenSlotSkipped,
 };
-use fork_choice::{ForkChoiceStore, InvalidAttestation, InvalidBlock, QueuedAttestation};
+use fork_choice::{
+    ForkChoiceStore, InvalidAttestation, InvalidBlock, PayloadVerificationStatus,
+    QueuedAttestation, SAFE_SLOTS_TO_UPDATE_JUSTIFIED,
+};
 use store::MemoryStore;
 use types::{
     test_utils::generate_deterministic_keypair, BeaconBlock, BeaconBlockRef, BeaconState,
@@ -268,7 +271,13 @@ impl ForkChoiceTest {
             .chain
             .fork_choice
             .write()
-            .on_block(current_slot, &block, block.canonical_root(), &state)
+            .on_block(
+                current_slot,
+                &block,
+                block.canonical_root(),
+                &state,
+                PayloadVerificationStatus::Verified,
+            )
             .unwrap();
         self
     }
@@ -303,7 +312,13 @@ impl ForkChoiceTest {
             .chain
             .fork_choice
             .write()
-            .on_block(current_slot, &block, block.canonical_root(), &state)
+            .on_block(
+                current_slot,
+                &block,
+                block.canonical_root(),
+                &state,
+                PayloadVerificationStatus::Verified,
+            )
             .err()
             .expect("on_block did not return an error");
         comparison_func(err);