test: add non-loopback IPv6 cases to isLoopback test

Signed-off-by: Daijiro Wachi <daijiro.wachi@gmail.com>

Author: watilde

test/parallel/test-internal-net-isLoopback.js

@@ -23,6 +23,10 @@ const loopbackNot = [
   '[2001:db8::1]',
   '[fe80::1]',
   '8.8.8.8',
+  '::2',
+  '[::2]',
+  '0:0:0:0:0:0:0:2',
+  '[0:0:0:0:0:0:0:2]',
 ];
 
 for (const address of loopback) {