get_names_for_var didn't do recursion for unnamed JOIN vars quite right;

get_names_for_var didn't do recursion for unnamed JOIN vars quite right;
got it wrong when the JOIN was in an outer query level.  Per example from
Laurie Burrow.  Also fix same issue in markTargetListOrigin.  I think the
latter is only a latent bug since we currently don't apply markTargetListOrigin
except at the outer level ... but should do it right anyway.