test: handle relative https redirect

Fix `internet/test-inspector-help-page` to handle the relative
redirect of `https://nodejs.org/en/docs/inspector` to
`/en/docs/guides/debugging-getting-started`. Previously this
URL redirected to an absolute URL.

PR-URL: #51121
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Yagiz Nizipli <[email protected]>

Author: richardlau

test/internet/test-inspector-help-page.js

@@ -18,7 +18,7 @@ function check(url, cb) {
     assert(res.statusCode >= 200 && res.statusCode < 400);
 
     if (res.statusCode >= 300)
-      return check(res.headers.location, cb);
+      return check(new URL(res.headers.location, url), cb);
 
     let result = '';