tests: Drop a slightly suspect GResolver test

This test will only work on machines which have IPv6 enabled and have a
local IPv6 interface with ID 1. On machines which don’t (such as AWS
servers, which we run CI tests on), the GResolver tests will fail with
G_RESOLVER_ERROR_INVALID. We can’t differentiate this kind of failure
(where we’d want to skip the test) from an actual failure (where we’d
want to fail the test), so the only other option is to drop this
particular test vector. I don’t think it’s a significant loss.

This is the last fix needed to get our CI tests working reliably on
jenkins.gnome.org.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://bugzilla.gnome.org/show_bug.cgi?id=795234