asyncio: fix thread-safety issue with cached_running_holder

Make `cached_running_holder` and `cached_running_holder_tsid` thread local.

Co-authored-by: renpeng <renpeng@xiaobing.ai>
Co-authored-by: Sam Gross <colesbury@gmail.com>

Modules/_asynciomodule.c

@@ -34,8 +34,8 @@ static PyObject *asyncio_CancelledError;
 static PyObject *context_kwname;
 static int module_initialized;
 
-static PyObject *cached_running_holder;
-static volatile uint64_t cached_running_holder_tsid;
+static Py_DECL_THREAD PyObject *cached_running_holder;
+static Py_DECL_THREAD uint64_t cached_running_holder_tsid;
 
 /* Counter for autogenerated Task names */
 static uint64_t task_name_counter = 0;