`CHECK`-failures during Grappler's `IsSimplifiableReshape` in Tensorflow
### Impact
The Grappler optimizer in TensorFlow can be used to cause a denial of service by altering a `SavedModel` such that `IsSimplifiableReshape`
https://github.com/tensorflow/tensorflow/blob/a1320ec1eac186da1d03f033109191f715b2b130/tensorflow/core/grappler/optimizers/constant_folding.cc#L1687-L1742 would trigger `CHECK` failures.
### Patches
We have patched the issue in GitHub commits ebc1a2ffe5a7573d905e99bd0ee3568ee07c12c1
https://github.com/tensorflow/tensorflow/commit/ebc1a2ffe5a7573d905e99bd0ee3568ee07c12c1, 1fb27733f943295d874417630edd3b38b34ce082
https://github.com/tensorflow/tensorflow/commit/1fb27733f943295d874417630edd3b38b34ce082, and 240655511cd3e701155f944a972db71b6c0b1bb6
https://github.com/tensorflow/tensorflow/commit/240655511cd3e701155f944a972db71b6c0b1bb6.
The fix will be included in TensorFlow 2.8.0. We will also cherrypick this commit on TensorFlow 2.7.1, TensorFlow 2.6.3, and TensorFlow 2.5.3, as these are also affected and still in supported range.
### For more information
Please consult our security guide
https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md for more information regarding the security model and how to contact us with issues and questions.