Use E for EthSpec globally (#5264)

* Use `E` for `EthSpec` globally

* Fix tests

* Merge branch 'unstable' into e-ethspec

* Merge branch 'unstable' into e-ethspec

# Conflicts:
#	beacon_node/execution_layer/src/engine_api.rs
#	beacon_node/execution_layer/src/engine_api/http.rs
#	beacon_node/execution_layer/src/engine_api/json_structures.rs
#	beacon_node/execution_layer/src/test_utils/handle_rpc.rs
#	beacon_node/store/src/partial_beacon_state.rs
#	consensus/types/src/beacon_block.rs
#	consensus/types/src/beacon_block_body.rs
#	consensus/types/src/beacon_state.rs
#	consensus/types/src/config_and_preset.rs
#	consensus/types/src/execution_payload.rs
#	consensus/types/src/execution_payload_header.rs
#	consensus/types/src/light_client_optimistic_update.rs
#	consensus/types/src/payload.rs
#	lcli/src/parse_ssz.rs

testing/ef_tests/src/cases/operations.rs

@@ -38,8 +38,8 @@ struct ExecutionMetadata {
 
 /// Newtype for testing withdrawals.
 #[derive(Debug, Clone, Deserialize)]
-pub struct WithdrawalsPayload<T: EthSpec> {
-    payload: FullPayload<T>,
+pub struct WithdrawalsPayload<E: EthSpec> {
+    payload: FullPayload<E>,
 }
 
 #[derive(Debug, Clone)]

testing/ef_tests/src/cases/shuffling.rs

@@ -6,26 +6,26 @@ use std::marker::PhantomData;
 use swap_or_not_shuffle::{compute_shuffled_index, shuffle_list};
 
 #[derive(Debug, Clone, Deserialize)]
-pub struct Shuffling<T> {
+pub struct Shuffling<E> {
     pub seed: String,
     pub count: usize,
     pub mapping: Vec<usize>,
     #[serde(skip)]
-    _phantom: PhantomData<T>,
+    _phantom: PhantomData<E>,
 }
 
-impl<T: EthSpec> LoadCase for Shuffling<T> {
+impl<E: EthSpec> LoadCase for Shuffling<E> {
     fn load_from_dir(path: &Path, _fork_name: ForkName) -> Result<Self, Error> {
         yaml_decode_file(&path.join("mapping.yaml"))
     }
 }
 
-impl<T: EthSpec> Case for Shuffling<T> {
+impl<E: EthSpec> Case for Shuffling<E> {
     fn result(&self, _case_index: usize, _fork_name: ForkName) -> Result<(), Error> {
         if self.count == 0 {
             compare_result::<_, Error>(&Ok(vec![]), &Some(self.mapping.clone()))?;
         } else {
-            let spec = T::default_spec();
+            let spec = E::default_spec();
             let seed = hex::decode(&self.seed[2..])
                 .map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))?;