Add system test for dual-stack-servers with possible DNAME response

Add system test for dual-stack-servers with possible DNAME response

Create a zone that triggers DNAME owner name checks in a zone that
is only reachable using a dual stack server.  The answer contains
a name that is higher in the tree than the query name.

e.g.
	foo.v4only.net.	CNAME	v4only.net.
	v4only.net.	A	10.0.0.1

ns4 is serving the test zone (ipv4-only)
ns6 is the root server for this test (dual stacked)
ns7 is acting as the dual stack server (dual stacked)
ns9 is the server under test (ipv6-only)

(cherry picked from commit f946133ec9792fe64b8000a7515e846f7f2a3b83)