Read-through cache in WASM memory for tables holding static data

Let us opt-in to a specific table behavior where data is read-through cached in WASM memory, and held between reducer invocations. This would be used for mostly-static data like navmesh data, terrain heightmap data, collider data, etc.

It would even be ok if this means writes to these tables become extremely slow in order to invalidate caches in all the WASM instances, because these tables would almost never be written to.