HPCC-10142 Support queryLogicalFilename on hthor

Build superfile name structure to enable mapping of subfiles into supers

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-10142 Support queryLogicalFilename on hthor

Minor improvement following code review

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #6483 from richardkchapman/hthor-logical-filename

HPCC-10142 Support queryLogicalFilename on hthor

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>