Allow any named*.conf file as a system test artifact

This allows rendering multiple named*.conf files using the jinja2
template engine at test start and then simply copying the required
config to named.conf as needed.

(cherry picked from commit d6d6db52e3)

bin/tests/system/conftest.py

@@ -309,7 +309,7 @@ def logger(request, system_test_name):
 def expected_artifacts(request):
     common_artifacts = [
         ".libs/*",  # possible build artifacts, see GL #5055
-        "ns*/named.conf",
+        "ns*/named*.conf",
         "ns*/named.memstats",
         "ns*/named.run",
         "ns*/named.run.prev",