HPCC-11024 Reorder class to improve 64bit packing

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #5535 from ghalliday/issue11024

HPCC-11024 Reorder class to improve 64bit packing

Reviewed-By: Jake Smith <jake.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>