Revert "Fix permission tests for views/tables proven empty by constraint exclusion."

This reverts commit 15b0421002624919c62ae3c6574af2a8452bf6c4.  Per
complaint from Robert Haas, that patch caused crashes on appendrel
cases, and it didn't fix all forms of the problem anyway.  Consensus
is we'll leave this problem alone in the back branches, at least
for now.