test: fix flaky http2-flow-control test

Backport-PR-URL: #22850
PR-URL: #20556
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: apapirovski

test/parallel/test-http2-misbehaving-flow-control-paused.js

@@ -70,8 +70,6 @@ server.on('stream', (stream) => {
     client.destroy();
   }));
   stream.on('end', common.mustNotCall());
-  stream.respond();
-  stream.end('ok');
 });
 
 server.listen(0, () => {