net/http: fix unclosed Listener leak in ListenAndServeTLS

Fixes #23002

Change-Id: I87e72833757497aff49117dd40629cb7ec49e6e7
Reviewed-on: https://go-review.googlesource.com/81955Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/net/http/server.go

@@ -2998,6 +2998,8 @@ func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error {
 		return err
 	}
 
+	defer ln.Close()
+
 	return srv.ServeTLS(tcpKeepAliveListener{ln.(*net.TCPListener)}, certFile, keyFile)
 }