fix: remove duplicate constraint

evm_arithmetization/src/keccak/keccak_stark.rs

@@ -275,14 +275,10 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for KeccakStark<F
         let local_values = vars.get_local_values();
         let next_values = vars.get_next_values();
 
-        // The filter must be 0 or 1.
-        let filter = local_values[reg_step(NUM_ROUNDS - 1)];
-        yield_constr.constraint(filter * (filter - P::ONES));
-
         // If this is not the final step, the filter must be off.
         let final_step = local_values[reg_step(NUM_ROUNDS - 1)];
         let not_final_step = P::ONES - final_step;
-        yield_constr.constraint(not_final_step * filter);
+        yield_constr.constraint(not_final_step * final_step);
 
         // If this is not the final step or a padding row,
         // the local and next timestamps must match.
@@ -446,15 +442,10 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for KeccakStark<F
         let local_values = vars.get_local_values();
         let next_values = vars.get_next_values();
 
-        // The filter must be 0 or 1.
-        let filter = local_values[reg_step(NUM_ROUNDS - 1)];
-        let constraint = builder.mul_sub_extension(filter, filter, filter);
-        yield_constr.constraint(builder, constraint);
-
         // If this is not the final step, the filter must be off.
         let final_step = local_values[reg_step(NUM_ROUNDS - 1)];
         let not_final_step = builder.sub_extension(one_ext, final_step);
-        let constraint = builder.mul_extension(not_final_step, filter);
+        let constraint = builder.mul_extension(not_final_step, final_step);
         yield_constr.constraint(builder, constraint);
 
         // If this is not the final step or a padding row,