When checking if an object is an instance of a an added intrinsic object such a uint8 typed array it would be useful to check the class id directly.

We can access the class id via JS_GetClassID but we can't compare with anything as the already defined tags are stored in an private unnamed enum.

This is currently rather brittle in rquckjs as typed arrays are checked by looking at the constructor name in global scope and calling qjs::JS_IsInstanceOf