bpo-9263: _PyXXX_CheckConsistency() use _PyObject_ASSERT() (GH-10108)

Use _PyObject_ASSERT() in:

* _PyDict_CheckConsistency()
* _PyType_CheckConsistency()
* _PyUnicode_CheckConsistency()

_PyObject_ASSERT() dumps the faulty object if the assertion fails
to help debugging.