test/ssl: use send()/recv()/EVUTIL_ERR_RW_RETRIABLE()/EVUTIL_SOCKET_ERROR() to fix win32 Fixes: https://ci.appveyor.com/project/azat/libevent/build/2.1.5.107/job/k70our1xdp0ym4dm#L1906 Fixes: ssl/bufferevent_connect_sleep