Fix another problem in 8.2 changes that allowed "one-time" qual conditions to

Fix another problem in 8.2 changes that allowed "one-time" qual conditions to
be checked at plan levels below the top; namely, we have to allow for Result
nodes inserted just above a nestloop inner indexscan.  Should think about
using the general Param mechanism to pass down outer-relation variables, but
for the moment we need a back-patchable solution.  Per report from Phil Frost.