Split off from issue213.
Quoting Malte in msg5862:
"The drop for bjolp [between 32- and 64-bit builds] surprised me a bit,
so I had a look how it stores a landmark data, and it uses a
PerStateInformation<vector<bool>>, which is very wasteful because we
pay the vector overhead for every single state. For our state
representation, we moved from SegmentedVector to SegmentedArrayVector
for this reason, and it made a big difference. We should probably do a
similar thing here, i.e., have something like PerStateInformation
optimized for same-size arrays. (And because this is a vector<bool>, we
additionally need to pack individual bits.)"