test: refactor test-dns-regress-6244.js

* Move from parallel to internet because it performs a DNS query
* Provide link to relevant issue in comments
* Remove unnecessary explicit no-op function

PR-URL: nodejs#13058
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

test/parallel/test-dns-regress-6244.js → test/internet/test-dns-regress-6244.js

@@ -23,5 +23,6 @@
 const common = require('../common');
 const dns = require('dns');
 
-// Should not segfault, see #6244.
-dns.resolve4('127.0.0.1', common.mustCall(() => { }));
+// Should not segfault.
+// Ref: https://github.com/nodejs/node-v0.x-archive/issues/6244
+dns.resolve4('127.0.0.1', common.mustCall());