Server does not require hint() for min()/max() when IDHACK is used

In SERVER-39567 we changed min()/max() to require a hint(), but kay.kim discovered that this is not enforced when IDHACK is used.

I don't think there's an incorrect results bug here (similar to the linked ticket) but this is undesirable.

Repro:

db.c.find({_id: 5}).max({_id: 1}).explain()