LibJS: Add the Symbol.species getter to the appropriate built-ins

Author: https://github.com/IdanHo
Commit: aefb7995f1
Pull-request: https://github.com/SerenityOS/serenity/pull/7878
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibJS/Runtime/RegExpConstructor.h

@@ -23,6 +23,8 @@ public:
 
 private:
     virtual bool has_constructor() const override { return true; }
+
+    JS_DECLARE_NATIVE_GETTER(symbol_species_getter);
 };
 
 }