`CHECK`-failures during Grappler's `SafeToRemoveIdentity` in Tensorflow

ImpactThe Grappler optimizer in TensorFlow can be used to cause a denial of service by altering a SavedModel such that SafeToRemoveIdentity would trigger CHECK failures. PatchesWe have patched the issue in GitHub commit 92dba16749fae36c246bec3f9ba474d9ddeb7662.The fix will be included in TensorFl...