LibJS: Add Object::fast_is<Set>() and Object::fast_is<Map>()

These are often hit by object serialization code path.

Author: kalenikaliaksandr

Libraries/LibJS/Runtime/Map.h

@@ -25,6 +25,8 @@ class JS_API Map : public Object {
 
     virtual ~Map() override = default;
 
+    virtual bool is_map_object() const final { return true; }
+
     void map_clear();
     bool map_remove(Value const&);
     Optional<Value> map_get(Value const&) const;
@@ -116,4 +118,7 @@ class JS_API Map : public Object {
     HashMap<Value, Value, ValueTraits> m_entries;
 };
 
+template<>
+inline bool Object::fast_is<Map>() const { return is_map_object(); }
+
 }

Libraries/LibJS/Runtime/Object.h

@@ -227,6 +227,8 @@ class JS_API Object : public Cell
     virtual bool is_ecmascript_function_object() const { return false; }
     virtual bool is_array_iterator() const { return false; }
     virtual bool is_raw_json_object() const { return false; }
+    virtual bool is_set_object() const { return false; }
+    virtual bool is_map_object() const { return false; }
 
     virtual bool eligible_for_own_property_enumeration_fast_path() const { return true; }
 

Libraries/LibJS/Runtime/Set.h

@@ -24,6 +24,8 @@ class JS_API Set : public Object {
     virtual void initialize(Realm&) override;
     virtual ~Set() override = default;
 
+    virtual bool is_set_object() const final { return true; }
+
     // NOTE: Unlike what the spec says, we implement Sets using an underlying map,
     //       so all the functions below do not directly implement the operations as
     //       defined by the specification.
@@ -59,4 +61,7 @@ struct SetRecord {
 ThrowCompletionOr<SetRecord> get_set_record(VM&, Value);
 bool set_data_has(GC::Ref<Set>, Value);
 
+template<>
+inline bool Object::fast_is<Set>() const { return is_set_object(); }
+
 }