message: Copy pulled up filter from LHS to push down in RHS, also pulled up filters from LHS and RHS to the above levels.
diff: @@ -32,10 +32,22 @@ unique_ptr<LogicalOperator> FilterPushdown::PushdownCrossProduct(unique_ptr<Logi
  join_conditions.push_back(move(f->filter));
  }
  }
  + // need to clear up the filters for subsequent use, e.g., filters pull up
  + filters.clear();
  }
  op->children[0] = left_pushdown.Rewrite(move(op->children[0]));
  +
  + //appending filters from the LHS to pushdown into the RHS
  + combiner.Append(left_pushdown.combiner_pullup);
  + GenerateFilters();
  +
  + //FIXME case filters are in the RHS, they are not pulled up and then pushed down to the LHS
  op->children[1] = right_pushdown.Rewrite(move(op->children[1]));
  + //appending filters from both LHS and RHS to pull up
  + combiner_pullup.Append(left_pushdown.combiner_pullup);
  + combiner_pullup.Append(right_pushdown.combiner_pullup);
  +
  if (join_conditions.size() > 0) {
  // join conditions found: turn into inner join
  return LogicalComparisonJoin::CreateJoin(JoinType::INNER, move(op->children[0]), move(op->children[1]),
  