The representation of non empty interfaces defined in the interpreter is now identical between refType() and frameType() functions, which are used to generate interpreter objects.
Fixes#1447 and #1426.
This test (assert2.go) display 2 separate issues:
1. assert2.go L28: Type assert tries to set an `interface{}` to a `valueInterface`. The typing here is complex, we have a valueT(strings.Builder) wrapped in a ptrT wrapped in a src iface wrapped in a valueT(interface{}). Type assert fails to realise that the `valueT` `interface{}` is wrapping the `valueInterface`.
2. assert2.go L29: `genValueBinMethodOnInterface` does not try and get the bin method, as the `typ.node` (`ptrT` or a `valueT`(`string.Builder`)) is set. In this case the src iface is called with a receiver argument. To fix this the method is looked for first if possible, and only if not found does it fall back to the `defaultGen`.
Fixes#1227
Marc Vertes
Nicholas Wiersma