[Python-checkins] cpython: Use identifier API for PyObject_GetAttrString.

["Martin v. Löwis"]

> - In Modules/_json.c, line 1126, _Py_identifier(strict) is
> declared but not used, and there are 5 other possible replacements.

Antoine reverted this in 8ed6a627a834. I think I started doing them,
then noticed that this is an initializer, so it's likely not called
that often.

In any case, I'll make several more passes over the code base, so
I may revisit this point.

> - In Objects/typeobject.c, line 6318, it seems that
> _PyObject_GetAttrId could be used directly

Good point. Fixed in c060261a65b8.

Regards,
Martin