bpo-36957: Add _PyLong_Rshift() and _PyLong_Lshift(). (GH-13416)

diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index adb9b80..4ff43bb 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -463,13 +463,13 @@
                  */
                 PyObject *temp;
 
-                temp = PyNumber_Lshift(ww, _PyLong_One);
+                temp = _PyLong_Lshift(ww, 1);
                 if (temp == NULL)
                     goto Error;
                 Py_DECREF(ww);
                 ww = temp;
 
-                temp = PyNumber_Lshift(vv, _PyLong_One);
+                temp = _PyLong_Lshift(vv, 1);
                 if (temp == NULL)
                     goto Error;
                 Py_DECREF(vv);