LongLong, LongDouble, DoubleDouble and DoubleLong maps might use array of doubled size
as table to layout keys and values in parallel. They should override this method to return
true.
IntInt and smaller maps would better use array of larger primitives (
long[] in
this particular case), because it 1) guarantees that each key and value pair lay on the same
cache line and 2) allows higher max capacity.
It is UpdatableQHash's concern in order to treat edge cases of capacities near to Java
array size limit correctly.