Fix type inferencing for outer class type parameter references

[eric-milles]

Consider the following (GROOVY-10646 excerpt):

interface Output<T> {
  T getT()
}
abstract class WhereDSL<Type> {
  abstract Type where()
}
abstract class Input<T> extends WhereDSL<ReferencesOuterClassTP> {
  class ReferencesOuterClassTP implements Output<T> {
    @Override T getT() {
      return null
    }
  }
}

class Model {
}

void m(Input<Model> input) {
  def output = input.where()
  def result = output.getT()
  //  ^^^^^^ expect Model
}

Override method getT() makes reference to outer class type parameter T. "output" infers as ReferencesOuterClassTP but "result" does not infer as Model.

[eric-milles]