Implemented new interpreter instruction: exit_ok_last

This two new features combined can be used to make fast select count
 


ndb/include/kernel/AttributeHeader.hpp:
  Psuedo columns fragment & row_count
ndb/include/kernel/GlobalSignalNumbers.h:
  Impl. READ_ROWCOUNT
ndb/include/kernel/signaldata/TupKey.hpp:
  Remove unused pageId pageIndex and replace with lastRow flag
ndb/include/ndbapi/NdbOperation.hpp:
  New instruction for last_row
ndb/src/kernel/blocks/dbacc/Dbacc.hpp:
  REQ_ROWCOUNT
ndb/src/kernel/blocks/dbacc/DbaccInit.cpp:
  REQ_ROWCOUNT
ndb/src/kernel/blocks/dbacc/DbaccMain.cpp:
  REQ_ROWCOUNT
ndb/src/kernel/blocks/dblqh/Dblqh.hpp:
  REQ_ROWCOUNT + last row
ndb/src/kernel/blocks/dblqh/DblqhInit.cpp:
  REQ_ROWCOUNT
ndb/src/kernel/blocks/dblqh/DblqhMain.cpp:
  REQ_ROWCOUNT + last row
ndb/src/kernel/blocks/dbtup/Dbtup.hpp:
  Add readers for new psuedo columns
ndb/src/kernel/blocks/dbtup/DbtupExecQuery.cpp:
  Add readers for new psuedo columns
ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp:
  Add readers for new psuedo columns
ndb/src/ndbapi/NdbOperationDefine.cpp:
  Use exit ok (not ok_last)
ndb/src/ndbapi/NdbOperationExec.cpp:
  Use exit ok (not ok_last)
ndb/src/ndbapi/NdbOperationInt.cpp:
  New instruction