gh-108308: Replace PyDict_GetItem() with PyDict_GetItemRef() (#108309)

Replace PyDict_GetItem() calls with PyDict_GetItemRef()
or PyDict_GetItemWithError() to handle errors.

* Replace PyLong_AS_LONG() with _PyLong_AsInt()
  and check for errors.
* Check for PyDict_Contains() error.
* pycore_init_builtins() checks for _PyType_Lookup() failure.