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

ImpactThe Grappler optimizer in TensorFlow can be used to cause a denial of service by altering a SavedModel such that IsSimplifiableReshape would trigger CHECK failures. PatchesWe have patched the issue in GitHub commits ebc1a2ffe5a7573d905e99bd0ee3568ee07c12c1,...