bpo-30061: Check if PyObject_Size()/PySequence_Size()/PyMapping_Size() (#1096)

raised an error.

Replace them with using concrete types API that never fails if appropriate.

Modules/cjkcodecs/multibytecodec.c

@@ -1670,6 +1670,9 @@ _multibytecodec_MultibyteStreamWriter_writelines(MultibyteStreamWriterObject *se
         if (r == -1)
             return NULL;
     }
+    /* PySequence_Length() can fail */
+    if (PyErr_Occurred())
+        return NULL;
 
     Py_RETURN_NONE;
 }