Removing PRNG

As subject.

A downside is that PRNG was being used to control the initial counter value for the next pointer in queue elements.

Now I have to use an atomic add, which will I think be the ONLY use of atomic add in the code base, and it’ll mean a bottleneck on that counter in the queue state.

Nothing else for it, except per-thread state, and I can’t justify per-thread state to avoid one atomic add.