HPCC-10643 Don't generate HASH and SMART joins inside child queries

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #5557 from ghalliday/issue10643

HPCC-10643 Don't generate HASH and SMART joins inside child queries

Reviewed-By: Jake Smith <jake.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>