Removed CurlEpollFdTracker completely (#896)

CurlEpollFdTracker was added as a fix of another problem but it didn't help (a37c782).
Moreover it led to another crash in runtime from free_runtime_environment.

runtime/curl.cpp

@@ -1021,38 +1021,10 @@ void clear_contexts(array<CTX *> &contexts) {
   hard_reset_var(contexts);
 }
 
-class CurlEpollFdTracker : vk::not_copyable {
-public:
-  void add_fd(int fd) noexcept {
-    int64_t dummy{};
-    used_fds_.emplace_value(fd, dummy);
-  }
-
-  void remove_fd(int fd) noexcept {
-    used_fds_.unset(fd);
-  }
-
-  void dispose_all_fds_from_epoll() noexcept {
-    for (auto it : used_fds_) {
-      int fd = it.get_int_key();
-      epoll_remove(fd);
-      remove_fd(fd);
-    }
-    hard_reset_var(used_fds_);
-  }
-
-private:
-  CurlEpollFdTracker() = default;
-  friend class vk::singleton<CurlEpollFdTracker>;
-
-  array<int64_t> used_fds_;
-};
-
 void free_curl_lib() noexcept {
   dl::CriticalSectionGuard critical_section;
   clear_contexts(vk::singleton<CurlContexts>::get().easy_contexts);
   clear_contexts(vk::singleton<CurlContexts>::get().multi_contexts);
-  vk::singleton<CurlEpollFdTracker>::get().dispose_all_fds_from_epoll();
   vk::singleton<CurlMemoryUsage>::get().total_allocated = 0;
 }
 
@@ -1168,8 +1140,7 @@ static int curl_epoll_cb(int fd, void *data, event_t *ev) {
 }
 
 static int curl_socketfunction_cb(CURL */*easy*/, curl_socket_t fd, int action, void *userp, void */*socketp*/) {
-  dl::CriticalSectionGuard critical_section;
-
+  dl::CriticalSectionGuard guard;
   auto *curl_request = static_cast<CurlRequest *>(userp);
   php_assert(curl_request);
 
@@ -1186,12 +1157,10 @@ static int curl_socketfunction_cb(CURL */*easy*/, curl_socket_t fd, int action,
       }
       epoll_insert(fd, events);
       epoll_sethandler(fd, 0, curl_epoll_cb, curl_request);
-      vk::singleton<CurlEpollFdTracker>::get().add_fd(fd);
       break;
     }
     case CURL_POLL_REMOVE: {
       epoll_remove(fd);
-      vk::singleton<CurlEpollFdTracker>::get().remove_fd(fd);
       break;
     }
     default: