gh-100649: Update native_thread_id after fork (gh-100650)

Update native_thread_id after fork

Author: P403n1x87

Misc/NEWS.d/next/Core and Builtins/2022-12-31-23-32-09.gh-issue-100649.C0fY4S.rst

@@ -0,0 +1 @@
+Update the native_thread_id field of PyThreadState after fork.

Modules/posixmodule.c

@@ -595,6 +595,10 @@ PyOS_AfterFork_Child(void)
     PyThreadState *tstate = _PyThreadState_GET();
     _Py_EnsureTstateNotNULL(tstate);
 
+#ifdef PY_HAVE_THREAD_NATIVE_ID
+    tstate->native_thread_id = PyThread_get_thread_native_id();
+#endif
+
     status = _PyEval_ReInitThreads(tstate);
     if (_PyStatus_EXCEPTION(status)) {
         goto fatal_error;