test: handle errors correctly in GC http test

In test-gc-http-client-timeout.js, res.resume is not a function if error
occurs. Remove the error handler.

PR-URL: nodejs#22185
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: oyyd

test/parallel/test-gc-http-client-timeout.js

@@ -39,7 +39,7 @@ function getall() {
       pathname: '/',
       port: server.address().port
     }, cb);
-    req.on('error', cb);
+
     req.setTimeout(10, function() {
       console.log('timeout (expected)');
     });