HPCC-11858 Add a #option to only report the filename tail from assert

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6194 from ghalliday/issue11858

HPCC-11858 Add a #option to only report the filename tail from assert

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>