message: Use heap.alloc where you can in list
  Summary: Previously several things made the complex/simple distinction when allocating. Move to using heap.alloc where we can.
diff: @@ -88,13 +88,13 @@ impl<'v> FromValue<'v> for List<'v> {
  impl<'v, V: AllocValue<'v>> AllocValue<'v> for Vec<V> {
  fn alloc_value(self, heap: &'v Heap) -> Value<'v> {
  - heap.alloc_complex(List::new(self.into_map(|x| x.alloc_value(heap))))
  + heap.alloc(List::new(self.into_map(|x| x.alloc_value(heap))))
  }
  }
  impl<'v, V: AllocFrozenValue> AllocFrozenValue for Vec<V> {
  fn alloc_frozen_value(self, heap: &FrozenHeap) -> FrozenValue {
  - heap.alloc_simple(FrozenList {
  + heap.alloc(FrozenList {
  content: self.into_map(|x| x.alloc_frozen_value(heap)),
  })
  }
  