fix(hgraph): refactor label remap handling in SetImmutable (#1550)

Signed-off-by: baoyuan <[email protected]>

Author: misaka0714

src/algorithm/hgraph.cpp

@@ -1277,9 +1277,7 @@ HGraph::deserialize_label_info(StreamReader& reader) const {
         StreamReader::ReadObj(reader, key);
         InnerIdType value;
         StreamReader::ReadObj(reader, value);
-        if (not this->immutable_) {
-            this->label_table_->label_remap_.emplace(key, value);
-        }
+        this->label_table_->label_remap_.emplace(key, value);
     }
 }
 
@@ -2012,9 +2010,6 @@ HGraph::SetImmutable() {
     this->neighbors_mutex_.reset();
     this->neighbors_mutex_ = std::make_shared<EmptyMutex>();
     this->searcher_->SetMutexArray(this->neighbors_mutex_);
-    this->label_table_->use_reverse_map_ = false;
-    STLUnorderedMap<LabelType, InnerIdType> empty_remap(allocator_);
-    this->label_table_->label_remap_.swap(empty_remap);
     this->immutable_ = true;
 }