jerryx_arg_transform_optional does not advance iterator in case the value is undefined

[martijnthe]

I would expect in this line to pop the iterator if js_arg is undefined.
Otherwise there can only be a single optional argument. Another consequence is that jerryx_arg_transform_optional does not work together with jerryx_arg_transform_object_properties because the iterator does not get advanced when an optional arg is undefined...

It looks like the unit test doesn't have either of these scenarios as a test case.

@jiangzidong do you agree this is a bug?

[jiangzidong]

Hi @martijnthe , yes, I think it is a bug. Sorry for that.
And could you help fix it since I dont have the dev env in my hand now.

[martijnthe]

@jiangzidong yes, I'll take care of it. Thanks for confirming! Hope you are doing well :)