Bulk signature verification (#507)

* Add basic block processing benches

* Start reviving state processing benches

* Fix old block builders

* Add optimization for faster pubkey add

* Tidy benches, add another

* Add extra block processing bench

* Start working on faster BLS scheme

* Add partially complete sig verify optimization

* Add .gitignore to state processing

* Add progress on faster signature verification

* Fix SignatureSet for fake_crypto

* Tidy attester slashings sig set

* Tidy bulk signature verifier

* Refactor signature sets to be cleaner

* Start threading SignatureStrategy through code

* Add (empty) test dir

* Move BenchingBlockBuilder

* Add initial block signature verification tests

* Add tests for bulk signature verification

* Start threading SignatureStrategy in block proc.

* Refactor per_block_processing errors

* Use sig set tuples instead of lists of two

* Remove dead code

* Thread VerifySignatures through per_block_processing

* Add bulk signature verification

* Introduce parallel bulk signature verification

* Expand state processing benches

* Fix additional compile errors

* Fix issue where par iter chunks is 0

* Update milagro_bls dep

* Remove debugs, code fragment in beacon chain

* Tidy, add comments to block sig verifier

* Fix various PR comments

* Add block_root option to per_block_processing

* Fix comment in block signature verifier

* Fix comments from PR review

* Remove old comment

* Fix comment

eth2/utils/bls/src/fake_aggregate_signature.rs

@@ -2,6 +2,7 @@ use super::{
     fake_aggregate_public_key::FakeAggregatePublicKey, fake_signature::FakeSignature,
     BLS_AGG_SIG_BYTE_SIZE,
 };
+use milagro_bls::G2Point;
 use serde::de::{Deserialize, Deserializer};
 use serde::ser::{Serialize, Serializer};
 use serde_hex::{encode as hex_encode, PrefixedHexVisitor};
@@ -14,6 +15,8 @@ use ssz::{ssz_encode, Decode, DecodeError, Encode};
 #[derive(Debug, PartialEq, Clone, Default, Eq)]
 pub struct FakeAggregateSignature {
     bytes: Vec<u8>,
+    /// Never used, only use for compatibility with "real" `AggregateSignature`.
+    pub point: G2Point,
 }
 
 impl FakeAggregateSignature {
@@ -26,9 +29,14 @@ impl FakeAggregateSignature {
     pub fn zero() -> Self {
         Self {
             bytes: vec![0; BLS_AGG_SIG_BYTE_SIZE],
+            point: G2Point::new(),
         }
     }
 
+    pub fn as_raw(&self) -> &Self {
+        &self
+    }
+
     /// Does glorious nothing.
     pub fn add(&mut self, _signature: &FakeSignature) {
         // Do nothing.
@@ -69,6 +77,7 @@ impl FakeAggregateSignature {
         } else {
             Ok(Self {
                 bytes: bytes.to_vec(),
+                point: G2Point::new(),
             })
         }
     }