ndb/src/kernel/blocks/dbtux/Dbtux.hpp:
  use pool of lock ops (like tupscan) instead of array of 992
ndb/src/kernel/blocks/dbtux/DbtuxDebug.cpp:
  use pool of lock ops (like tupscan) instead of array of 992
ndb/src/kernel/blocks/dbtux/DbtuxGen.cpp:
  use pool of lock ops (like tupscan) instead of array of 992
ndb/src/kernel/blocks/dbtux/DbtuxScan.cpp:
  use pool of lock ops (like tupscan) instead of array of 992
ndb/src/kernel/vm/DLFifoList.hpp:
  add Head::isEmpty