add historical summaries (#3865)

* add historical summaries

* fix tree hash caching, disable the sanity slots test with fake crypto

* add ssz static HistoricalSummary

* only store historical summaries after capella

* Teach `UpdatePattern` about Capella

* Tidy EF tests

* Clippy

Co-authored-by: Michael Sproul <michael@sigmaprime.io>

testing/ef_tests/src/handler.rs

@@ -374,6 +374,11 @@ impl<E: EthSpec + TypeName> Handler for SanitySlotsHandler<E> {
     fn handler_name(&self) -> String {
         "slots".into()
     }
+
+    fn is_enabled_for_fork(&self, fork_name: ForkName) -> bool {
+        // Some sanity tests compute sync committees, which requires real crypto.
+        fork_name == ForkName::Base || cfg!(not(feature = "fake_crypto"))
+    }
 }
 
 #[derive(Derivative)]