r2.13 cherry-pick: 7a0fa5541fd "* Fix memory free error in tpu_execute.cc when there are zero addresses   returned by TpuEmbedding. * Adding VLOGs to tpu_execute.cc for improving debugging."
Refer to the original commit: https://github.com/tensorflow/tensorflow/commit/7a0fa5541fdeb67cba9ae2ef13a7dd507da58f76