Update the CNAME chain test to correspond to the changed behavior,
because now named returns SERVFAIL when hitting the maximum query
restarts limit (e.g. happening when following a long CNAME chain).
In the current test auth will hit the limit and return partial data
with a SERVFAIL code, while the resolver will return no data with
a SERVFAIL code after auth returns SERVFAIL to it.
7751c7eca6