HPCC-11857 Roxie gives assert error if try to execute suspended query

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #6193 from richardkchapman/roxie-suspended-assert

HPCC-11857 Roxie gives assert error if try to execute suspended query

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>