Some changes were made to private functions which may affect plugins which access them:

- ``FixtureManager._getautousenames()`` now takes a ``Node`` itself instead of the nodeid.
- ``FixtureManager.getfixturedefs()`` now takes the ``Node`` itself instead of the nodeid.
- The ``_pytest.nodes.iterparentnodeids()`` function is removed without replacement.
  Prefer to traverse the node hierarchy itself instead.
  If you really need to, copy the function from the previous pytest release.