HPCC-9622 Disable failing hthor test when6b.ecl

There's no prospect of fixing this until we retire hthor

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #5025 from richardkchapman/when6b-test

HPCC-9622 Disable failing hthor test when6b.ecl

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>