Remove old balance getter in ef_tests

Author: paulhauner

consensus/state_processing/src/per_epoch_processing/altair.rs

@@ -45,7 +45,6 @@ pub fn process_epoch<T: EthSpec>(
     // Slashings.
     process_slashings(
         state,
-        // FIXME(paul): could this be invalidated by rewards/penalties?
         participation_cache.current_epoch_total_active_balance(),
         spec.proportional_slashing_multiplier_altair,
         spec,

testing/ef_tests/src/cases/epoch_processing.rs

@@ -142,7 +142,9 @@ impl<E: EthSpec> EpochTransition<E> for Slashings {
             BeaconState::Altair(_) => {
                 process_slashings(
                     state,
-                    state.get_total_active_balance(spec)?,
+                    altair::ParticipationCache::new(state, spec)
+                        .unwrap()
+                        .current_epoch_total_active_balance(),
                     spec.proportional_slashing_multiplier_altair,
                     spec,
                 )?;