bpo-40137: _PyType_GetModuleByDef() doesn't check tp_flags (GH-25504)

_PyType_GetModuleByDef() no longer checks if types are heap types.

_PyType_GetModuleByDef() must only be called on a heap type created
by PyType_FromModuleAndSpec() or on its subclasses.
type_ready_mro() ensures that a static type cannot inherit from a
heap type.