http: don't destroy completed request

Calling destroy() on a completed ClientRequest, i.e.
once 'close' will be emitted should be a noop. Also
before emitting 'close' destroyed === true.

Fixes: https://github.com/nodejs/node/issues/32851

PR-URL: https://github.com/nodejs/node/pull/33120
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

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

@@ -41,6 +41,7 @@ server.listen(0, options.host, function() {
     // This space intentionally left blank
   });
   req.on('close', function() {
+    assert.strictEqual(req.destroyed, true);
     server.close();
   });
   function destroy() {