tests: enable temporary libunbound debug logging

src/common/dns_utils.cpp

@@ -357,6 +357,11 @@ DNSResolver DNSResolver::create()
   return DNSResolver();
 }
 
+void DNSResolver::set_debug_level(int level)
+{
+  ub_ctx_debuglevel(m_data->m_ub_context, level);
+}
+
 namespace dns_utils
 {