HPCC-8352 Allow divide by zero action to be configured

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-8352 Update comments to clarify the code

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-8352 Move DBZaction into eclrtl and more cleaning up

* Also introduce a mark/release into the bcdCriticalBlock so that
divide by zero exceptions don't cause roxie to run out of bcd stack

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4072 from ghalliday/issue8352

HPCC-8352 Allow divide by zero action to be configured

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>