Socket API drops expired timeouts for transfers queued behind a connection limit

I found a way to make libcurl silently and permanently drop a transfer's `CURLOPT_TIMEOUT_MS`/`CURLOPT_CONNECTTIMEOUT_MS` deadline. It happens when that transfer is queued behind a connection-count limit and the application drives libcurl through the event-driven `curl_multi_socket_action()` API …

// lib/multi.c:2316-2324
multistate(data, MSTATE_PENDING);
/* move from process to pending set */
Curl_uint32_bset_remove(&multi->process, data->mid);
Curl_uint32_bset_remove(&multi->dirty, data->mid);
Curl_uint32_bset_add(&multi->pending, data->mid);