rm class_db.h from resource.h

modules/gdscript/tests/gdscript_test_runner.cpp

@@ -40,6 +40,7 @@
 #include "core/core_globals.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access_pack.h"
+#include "core/object/class_db.h"
 #include "core/os/os.h"
 #include "core/string/string_builder.h"
 #include "scene/resources/packed_scene.h"