message: Initialoize all the aggregation outputs
  A block can have multiple outputs and a assign/aggregation contraction transition could happen on any of these outputs. Make sure all the output aggregations are properly initialized.
diff: @@ -44,15 +44,10 @@ void AggregationBlockOutputInitialization(const stripe::Block* const block,
  }
  std::vector<const Refinement*> outRefs = block->ref_outs(true);
  - // We should handle only when there is one output (aggregation operation).
  - if (outRefs.size() != 1) {
  - return;
  - }
  -
  - const Refinement* dest = outRefs[0];
  + for (const Refinement* dest : outRefs) {
  std::string aggOp = dest->agg_op;
  if (aggOp != "add" && aggOp != "mul" && aggOp != "max" && aggOp != "min") {
  - return;
  + continue;
  }
  auto prevRefIter = prevBlock->ref_by_into(dest->from);
  @@ -71,6 +66,7 @@ void AggregationBlockOutputInitialization(const stripe::Block* const block,
  }
  }
  }
  +}
  void AggregationBlockOutputInitializationPass::Apply(CompilerState* state) const {
  auto reqs = stripe::FromProto(options_.reqs());
  