Set a default for datasets end_of_sequence.

While all datasets carefully set the end_of_sequence to true at the
appropriate time, some datasets might forget to set it to false in the normal
case. In order to avoid potential undefined behavior, we set the
end_of_sequence variable to be false by default.

PiperOrigin-RevId: 158337799

tensorflow/core/kernels/iterator_ops.cc

@@ -307,7 +307,7 @@ class IteratorGetNextOp : public AsyncOpKernel {
       core::ScopedUnref unref_iterator(iterator);
 
       std::vector<Tensor> components;
-      bool end_of_sequence;
+      bool end_of_sequence = false;
 
       IteratorContext::Params params;
       params.env = ctx->env();