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_public_key.rs

@@ -1,4 +1,5 @@
 use super::{PublicKey, BLS_PUBLIC_KEY_BYTE_SIZE};
+use milagro_bls::G1Point;
 
 /// A BLS aggregate public key.
 ///
@@ -7,6 +8,8 @@ use super::{PublicKey, BLS_PUBLIC_KEY_BYTE_SIZE};
 #[derive(Debug, Clone, Default)]
 pub struct FakeAggregatePublicKey {
     bytes: Vec<u8>,
+    /// Never used, only use for compatibility with "real" `AggregatePublicKey`.
+    pub point: G1Point,
 }
 
 impl FakeAggregatePublicKey {
@@ -14,10 +17,19 @@ impl FakeAggregatePublicKey {
         Self::zero()
     }
 
+    pub fn add_without_affine(&mut self, _public_key: &PublicKey) {
+        // No nothing.
+    }
+
+    pub fn affine(&mut self) {
+        // No nothing.
+    }
+
     /// Creates a new all-zero's aggregate public key
     pub fn zero() -> Self {
         Self {
             bytes: vec![0; BLS_PUBLIC_KEY_BYTE_SIZE],
+            point: G1Point::new(),
         }
     }
 
@@ -25,10 +37,18 @@ impl FakeAggregatePublicKey {
         // No nothing.
     }
 
-    pub fn as_raw(&self) -> &FakeAggregatePublicKey {
+    pub fn add_point(&mut self, _point: &G1Point) {
+        // No nothing.
+    }
+
+    pub fn as_raw(&self) -> &Self {
         &self
     }
 
+    pub fn into_raw(self) -> Self {
+        self
+    }
+
     pub fn as_bytes(&self) -> Vec<u8> {
         self.bytes.clone()
     }