fix PropertyDescriptor.copy

it fails in certain situation, breaks test added in following commit

compiler/frontend/src/org/jetbrains/jet/lang/descriptors/PropertySetterDescriptor.java

@@ -24,9 +24,6 @@ public class PropertySetterDescriptor extends PropertyAccessorDescriptor {
             boolean hasBody,
             boolean isDefault) {
         super(modality, visibility, correspondingProperty, annotations, "set-" + correspondingProperty.getName(), hasBody, isDefault);
-        if (isDefault) {
-            initializeDefault();
-        }
     }
 
     public void initialize(@NotNull ValueParameterDescriptor parameter) {

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DescriptorResolver.java

@@ -730,6 +730,7 @@ public class DescriptorResolver {
                 propertyDescriptor, Collections.<AnnotationDescriptor>emptyList(), propertyDescriptor.getModality(),
                 propertyDescriptor.getVisibility(),
                 false, true);
+        setterDescriptor.initializeDefault();
         return setterDescriptor;
     }