benchmark: fix async-resource benchmark

In the benchmark, because it performs asynchronous operations before
writing its HTTP replies, the underlying socket can be closed by the
peer before the response is written. Since 28e6626, that means
that attempting to `.end()` the HTTP response results in an uncaught
exception, breaking the benchmark.

Fix that by checking whether the response object has been destroyed
or not before attempting to call `.end()`.

nodejs#33591

benchmark/async_hooks/async-resource-vs-destroy.js

@@ -138,6 +138,7 @@ function getServeAwait(getCLS, setCLS) {
     setCLS(Math.random());
     await sleep(10);
     await read(__filename);
+    if (res.destroyed) return;
     res.setHeader('content-type', 'application/json');
     res.end(JSON.stringify({ cls: getCLS() }));
   };
@@ -148,6 +149,7 @@ function getServeCallbacks(getCLS, setCLS) {
     setCLS(Math.random());
     setTimeout(() => {
       readFile(__filename, () => {
+        if (res.destroyed) return;
         res.setHeader('content-type', 'application/json');
         res.end(JSON.stringify({ cls: getCLS() }));
       });