message: Add MySQL handshake timeout test.
diff: @@ -7,6 +7,7 @@ swoole_mysql_coro: connect timeout
  require __DIR__ . '/../include/bootstrap.php';
  go(function () {
  $mysql = new Swoole\Coroutine\MySQL;
  + // tcp connect timeout
  $s = microtime(true);
  $connected = $mysql->connect([
  'host' => '192.0.0.1',
  @@ -20,6 +21,20 @@ go(function () {
  assert(!$connected);
  assert($mysql->connected === false);
  assert($mysql->connect_errno === SOCKET_ETIMEDOUT);
  + // handshake timeout
  + $s = microtime(true);
  + $connected = $mysql->connect([
  + 'host' => REDIS_SERVER_HOST,
  + 'port' => REDIS_SERVER_PORT,
  + 'user' => MYSQL_SERVER_USER,
  + 'password' => MYSQL_SERVER_PWD,
  + 'database' => MYSQL_SERVER_DB,
  + 'timeout' => ($timeout = mt_rand(100, 500) / 1000)
  + ]);
  + assert(time_approximate($timeout, microtime(true) - $s));
  + assert(!$connected);
  + assert($mysql->connected === false);
  + assert($mysql->connect_errno === SOCKET_ETIMEDOUT);
  });
  Swoole\Event::wait();
  echo "DONE\n";
  