Rollup node: use a local cache per game for intermediate states

What

Each refutation game "player" now has a local cache for intermediate states.

Why

This allows to always start the next dissection from a previously computed state. Previously, intermediate states could disappear from the global cache if there were too many parallel refutation games.

The global state cache remains to share states among parallel refutation games.

How

YAC (yet another cache).

Manually testing the MR