Fix display of whole-row Var appearing at the top level of a SELECT list.

While we normally prefer the notation "foo.*" for a whole-row Var, that does
not work at SELECT top level, because in that context the parser will assume
that what is wanted is to expand the "*" into a list of separate target
columns, yielding behavior different from a whole-row Var.  We have to emit
just "foo" instead in that context.  Per report from Sokolov Yura.