When calling a function, if the input param is a "zero" instance, it is not set on the input. This is an issue where the param is an `interface{}` as a `nil` value is set instead of the zero value.
The actual solution for this is to remove the `if !val.IsZero()`, this however runs into an issue on `_test/struct48.go` where we have a zero recursive struct instance (`*interface{}`) and we have no way to get its real type. Should a way be figured out to keep tabs on the original type, the `if` can go away, and in the zero case of `genValueRecursiveInterfacePtrValue`, the actual zero type can be returned.
Fixes#1215
