[NSE-119] clean up on comments (#288)

Signed-off-by: Yuan Zhou <[email protected]>

native-sql-engine/cpp/src/codegen/arrow_compute/ext/hash_aggregate_kernel.cc

@@ -804,7 +804,9 @@ class HashAggregateKernel::Impl {
           post_process_projector_(post_process_projector),
           action_impl_list_(action_impl_list) {
       aggr_hash_table_ = std::make_shared<StringHashMap>(ctx->memory_pool());
+#ifdef DEBUG
       std::cout << "using string hashagg res" << std::endl;
+#endif
       batch_size_ = GetBatchSize();
       if (key_index_list.size() > 1) {
         aggr_key_unsafe_row = std::make_shared<UnsafeRow>(key_index_list.size());
@@ -859,9 +861,6 @@ class HashAggregateKernel::Impl {
               typed_key_in->null_count() == 0 ? true : !typed_key_in->IsNull(i);
         }
 
-        // for (int n = 0; n < aggr_key.size(); ++n) printf("%0X ",
-        // *(aggr_key.data() + n)); std::cout << std::endl;
-
         // 3. get key from hash_table
         int memo_index = 0;
         if (!aggr_key_validity) {