HPCC-9759 Remove the globalFold option (default always on)

There are so many places that constant folding is required that this
option has long outlived its lifetime.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4671 from ghalliday/issue9759

HPCC-9759 Remove the globalFold option (default always on)

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>