gh-112069: Make PySet_GET_SIZE to be atomic safe.

[corona10]

• Issue: Make set thread-safe in --disable-gil builds #112069

[corona10]

tp_richcompare already set locks for two sets, so making PySet_GET_SIZE to be atomic safe will be enough.

cpython/Objects/setobject.c

Lines 2094 to 2111 in 94444ea

	casePy_EQ:
	if (PySet_GET_SIZE(v) !=PySet_GET_SIZE(w))
	Py_RETURN_FALSE;
	if (v->hash!=-1&&
	((PySetObject*)w)->hash!=-1&&
	v->hash!= ((PySetObject*)w)->hash)
	Py_RETURN_FALSE;
	returnset_issubset(v, w);
	casePy_NE:
	r1=set_richcompare(v, w, Py_EQ);
	if (r1==NULL)
	returnNULL;
	r2=PyObject_IsTrue(r1);
	Py_DECREF(r1);
	if (r2<0)
	returnNULL;
	returnPyBool_FromLong(!r2);
	casePy_LE:

FYI, the same thing is applied for PyList_GET_SIZE, too.

cpython/Include/cpython/listobject.h

Lines 30 to 37 in 94444ea

	staticinlinePy_ssize_tPyList_GET_SIZE(PyObject*op){
	PyListObject*list=_PyList_CAST(op);
	#ifdefPy_GIL_DISABLED
	return_Py_atomic_load_ssize_relaxed(&(_PyVarObject_CAST(list)->ob_size));
	#else
	returnPy_SIZE(list);
	#endif
	}