* batch database key writes during `computeKey` calls
* log progress when there are many keys to update
* avoid evicting the vertex cache when traversing the trie for key
computation purposes
* avoid storing trivial leaf hashes that directly can be loaded from the
vertex
* avoid costly hike memory allocations for operations that don't need to
re-traverse it
* avoid unnecessary state checks (which might trigger unwanted state
root computations)
* disable optimize-for-hits due to the MPT no longer being complete at
all times
Jacek Sieka