Add QA test for node group modification of ndparams

Additionally, we run hbal if the htools tests are enabled (new
key). Note that hbal will directly exit, since there are no instances,
but at least it will load and parse the group details.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>