LibJS: Add NaN to global object

Author: https://github.com/linusg
Commit: a0da97cb5a
Pull-request: https://github.com/SerenityOS/serenity/pull/1570

Libraries/LibJS/Runtime/GlobalObject.cpp

@@ -18,6 +18,7 @@ GlobalObject::GlobalObject()
     put_native_function("gc", gc);
     put_native_function("isNaN", is_nan);
 
+    put("NaN", js_nan());
     put("console", heap().allocate<ConsoleObject>());
     put("Date", heap().allocate<DateConstructor>());
     put("Error", heap().allocate<ErrorConstructor>());