Faster attestation production (#838)

* Start adding interop genesis state to lcli

* Use more efficient method to generate genesis state

* Remove duplicate int_to_bytes32

* Add lcli command to change state genesis time

* Add option to allow VC to start with unsynced BN

* Set VC to do parallel key loading

* Don't default to dummy eth1 backend

* Add endpoint to dump operation pool

* Add metrics for op pool

* Remove state clone for slot notifier

* Add mem size approximation for tree hash cache

* Avoid cloning tree hash when getting head

* Avoid cloning tree hash when getting head

* Add working arena-based cached tree hash

* Add another benchmark

* Add pre-allocation for caches

* Make cache nullable

* Fix bugs in cache tree hash

* Add validator tree hash optimization

* Optimize hash_concat

* Make hash32_concat return fixed-len array

* Fix failing API tests

* Add new beacon state cache struct

* Add validator-specific cache

* Separate list and values arenas

* Add parallel validator registry hashing

* Remove MultiTreeHashCache

* Remove cached tree hash macro

* Fix failing tree hash test

* Address Michael's comments

* Add CachedTreeHash impl for ef tests

* Fix messy merge conflict

* Optimize attestation production

* Add first basic optimizations

* Fix SlotOutOfBounds error

* Resolved missed merge conflicts

* Fix another missed merge conflict

* Fix more merge conflict issues

* Add `StateSkipConfig`

* Fix test compile errors

* Add failing test

* Fix bug, make tests pass

* Add comment

* Delete unused function

* Replace deleted comment

beacon_node/rest_api/tests/test.rs

@@ -1,6 +1,6 @@
 #![cfg(test)]
 
-use beacon_chain::{BeaconChain, BeaconChainTypes};
+use beacon_chain::{BeaconChain, BeaconChainTypes, StateSkipConfig};
 use node_test_rig::{
     environment::{Environment, EnvironmentBuilder},
     testing_client_config, ClientConfig, ClientGenesis, LocalBeaconNode,
@@ -242,7 +242,10 @@ fn check_duties<T: BeaconChainTypes>(
     );
 
     let mut state = beacon_chain
-        .state_at_slot(epoch.start_slot(T::EthSpec::slots_per_epoch()))
+        .state_at_slot(
+            epoch.start_slot(T::EthSpec::slots_per_epoch()),
+            StateSkipConfig::WithStateRoots,
+        )
         .expect("should get state at slot");
 
     state.build_all_caches(spec).expect("should build caches");
@@ -469,7 +472,7 @@ fn beacon_state() {
         .client
         .beacon_chain()
         .expect("client should have beacon chain")
-        .state_at_slot(Slot::new(0))
+        .state_at_slot(Slot::new(0), StateSkipConfig::WithStateRoots)
         .expect("should find state");
     db_state.drop_all_caches();