get_parent segfaults when used from within systems

[Hexlord]

Describe the bug
Attempt to get parent of an entity within system iterator segfault crashes.

To Reproduce

auto ECS = flecs::world();
struct Comp {int Field;};
auto E1 = ECS.entity();
auto E2 = ECS.entity().child_of(E1).add<Comp>();
ECS.system("System name", "[in] Comp").iter([](iter &Iter) {
    for (auto Index : Iter) {
        entity Entity = Iter.entity(Index);
        entity_view Parent = Entity.get_parent(0);
    }
});
ECS.progress(1.0f);
ECS.progress(1.0f);
ECS.progress(1.0f);
ECS.progress(1.0f);

Expected behavior
No crash happens

Additional information
Bug introduced in this commit: 8b24d0d

[SanderMertens]

Fixed!