windows: fix req refcount for uv_pipe_connect

src/win/internal.h

@@ -110,6 +110,7 @@ void uv_process_endgames();
 
 #define DECREASE_PENDING_REQ_COUNT(handle)    \
   do {                                        \
+    assert(handle->reqs_pending > 0);         \
     handle->reqs_pending--;                   \
                                               \
     if (handle->flags & UV_HANDLE_CLOSING &&  \

src/win/pipe.c

@@ -317,6 +317,8 @@ static DWORD WINAPI pipe_connect_thread_proc(void* parameter) {
     uv_fatal_error(GetLastError(), "PostQueuedCompletionStatus");
   }
 
+  handle->reqs_pending++;
+
   return 0;
 }