removal of old translator - sub-string data type

the sub-string data type was only used in the old translator and is no
longer needed (the new translator uses the sub-string table entry flag);
the AssignSubStr and AssignListMix codes were also removed;
the maximum number of associated codes was reduced from 4 to 3;
the entries for the sub-string data type was removed from the convert
have need table and the expected error status table;
various checks for the sub-string data type was removed from the
translator support functions