Handle static methods

[francisbouvier]

Some methods are static, ie. can be called on the type itself, not on the instance.

For example:

Document.prototype.toString();

Right now, if the API defines a custom get_symbol_toStringTag this will leads to panic has the getter expect an instance as argument.

[krichprollsch]

I have found also URL.parse and URL.canParse
https://url.spec.whatwg.org/#url-class