test: add test for url

PR-URL: https://github.com/nodejs/node/pull/11999
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Prince John Wesley <princejohnwesley@gmail.com>

test/parallel/test-url-relative.js

@@ -4,6 +4,9 @@ const assert = require('assert');
 const inspect = require('util').inspect;
 const url = require('url');
 
+// when source is false
+assert.strictEqual(url.resolveObject('', 'foo'), 'foo');
+
 /*
  [from, path, expected]
 */