persistent connections aren't persistent at all

[tony2001]

Reproduce scenario:

1. run FPM with one child process.
2. execute this script:

  $T = new Tarantool("<tarantool_server>", <tarantool_port>);
  $T->connect();

3. ensure that php_stream_xport_connect() is called on each request with the same parameters, which means that the connection is reestablished each time.

tarantool.persistent INI option doesn't have any effect - it may be Off or On, the result is still the same.