Add DynArr256 which is a ndb-ish judy array
  Like the one used in ACC


storage/ndb/src/kernel/vm/Makefile.am:
  Add DynArr256
storage/ndb/src/kernel/vm/bench_pool.cpp:
  update benchpool program
storage/ndb/src/kernel/vm/DynArr256.cpp:
  New BitKeeper file ``storage/ndb/src/kernel/vm/DynArr256.cpp''
storage/ndb/src/kernel/vm/DynArr256.hpp:
  New BitKeeper file ``storage/ndb/src/kernel/vm/DynArr256.hpp''