Don't leak the original QTYPE to parent zone

Don't leak the original QTYPE to parent zone

When performing QNAME minimization, named now sends an NS
query for the original QNAME, to prevent the parent zone from
receiving the QTYPE.

For example, when looking up example.com/A, we now send NS queries
for both com and example.com before sending the A query to the
servers for example.com.  Previously, an A query for example.com
would have been sent to the servers for com.

Several system tests needed to be adjusted for the new query pattern:

- Some queries in the serve-stale test were sent to the wrong server.
- The synthfromdnssec test could fail due to timing issues; this
  has been addressed by adding a 1-second delay.
- The cookie test could fail due to the a change in the count of
  TSIG records received in the "check that missing COOKIE with a
  valid TSIG signed response does not trigger TCP fallback" test case.
- The GL #4652 regression test case in the chain system test depends
  on a particular query order, which no longer occurs when QNAME
  minimization is active. We now disable qname-minimization
  for that test.