As in e348e7ae5727a6da8678036d748e5c5af7deb6c9 for jsonb/plperl, prevent
putting a NaN into a jsonb numeric field.
Tests for this had been removed in
6278a2a262b63faaf47eb2371f6bcb5b6e3ff118, but in case they are ever
resurrected: This would change the output of the test1nan() function to
an error.