HPCC-12034 Constant fold x+0,x-0,x*1,x DIV 1

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6314 from ghalliday/issue12034

HPCC-12034 Constant fold x+0,x-0,x*1,x DIV 1

Reviewed-By: Jamie Noss <james.noss@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>