Fix fast_parent_copy. The caching is now more solid than before (and doesn't produce weird side effects. This also solves an issue with Lambdas. However, by fixing all of this we have broken some other things.

jedi/evaluate/representation.py

@@ -551,6 +551,7 @@ class FunctionExecution(Executed):
             else:
                 copied = helpers.fast_parent_copy(element)
                 copied.parent = self._scope_copy(copied.parent)
+                # TODO remove? Doesn't make sense, at least explain.
                 if isinstance(copied, pr.Function):
                     copied = Function(self._evaluator, copied)
             objects.append(copied)