gh-120321: Fix TSan reported races on gi_frame_state (gh-143128)

Author: colesbury

Objects/genobject.c

@@ -559,7 +559,7 @@ gen_set_exception(PyObject *typ, PyObject *val, PyObject *tb)
 static PyObject *
 gen_throw_current_exception(PyGenObject *gen)
 {
-    assert(gen->gi_frame_state == FRAME_EXECUTING);
+    assert(FT_ATOMIC_LOAD_INT8_RELAXED(gen->gi_frame_state) == FRAME_EXECUTING);
 
     PyObject *result;
     if (gen_send_ex2(gen, Py_None, &result, 1) == PYGEN_RETURN) {

Python/frame.c

@@ -109,7 +109,7 @@ _PyFrame_ClearExceptCode(_PyInterpreterFrame *frame)
     /* It is the responsibility of the owning generator/coroutine
      * to have cleared the enclosing generator, if any. */
     assert(frame->owner != FRAME_OWNED_BY_GENERATOR ||
-        _PyGen_GetGeneratorFromFrame(frame)->gi_frame_state == FRAME_CLEARED);
+           FT_ATOMIC_LOAD_INT8_RELAXED(_PyGen_GetGeneratorFromFrame(frame)->gi_frame_state) == FRAME_CLEARED);
     // GH-99729: Clearing this frame can expose the stack (via finalizers). It's
     // crucial that this frame has been unlinked, and is no longer visible:
     assert(_PyThreadState_GET()->current_frame != frame);