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

consensus/state_processing/src/common/slash_validator.rs

@@ -12,11 +12,11 @@ use types::{
 };
 
 /// Slash the validator with index `slashed_index`.
-pub fn slash_validator<T: EthSpec>(
-    state: &mut BeaconState<T>,
+pub fn slash_validator<E: EthSpec>(
+    state: &mut BeaconState<E>,
     slashed_index: usize,
     opt_whistleblower_index: Option<usize>,
-    ctxt: &mut ConsensusContext<T>,
+    ctxt: &mut ConsensusContext<E>,
     spec: &ChainSpec,
 ) -> Result<(), BlockProcessingError> {
     let epoch = state.current_epoch();
@@ -27,7 +27,7 @@ pub fn slash_validator<T: EthSpec>(
     validator.slashed = true;
     validator.withdrawable_epoch = cmp::max(
         validator.withdrawable_epoch,
-        epoch.safe_add(T::EpochsPerSlashingsVector::to_u64())?,
+        epoch.safe_add(E::EpochsPerSlashingsVector::to_u64())?,
     );
     let validator_effective_balance = validator.effective_balance;
     state.set_slashings(