numbered_state_heap_hash_map_factory): New class.
* src/tgbaalgos/gtec/nsheap.cc (numbered_state_heap_hash_map_factory):
Implement it.
* src/tgbaalgos/gtec/gtec.hh (emptiness_check::emptiness_check,
emptiness_check_shy::emptiness_check_shy): Take a
numbered_state_heap_factory argument.
* tgbaalgos/gtec/status.hh
(emptiness_check_status::emptiness_check_status): Likewise.
(emptiness_check_status::h): Make it a numbered_state_heap*.
* src/tgbaalgos/gtec/ce.cc, tgbaalgos/gtec/gtec.cc,
tgbaalgos/gtec/status.cc: Adjust uses of ecs_->h.