make autodiff 'sharp edges' tutorial executable with example invocati…

…ons (tensorflow#564)

- and remove ||  and && workarounds since they are now supported

README.md

@@ -57,7 +57,7 @@ Tutorial | Last Updated |
 [Protocol-Oriented Programming & Generics](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/protocol_oriented_generics.ipynb) | August 2019
 [Python Interoperability](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/python_interoperability.ipynb) | March 2019
 [Custom Differentiation](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/custom_differentiation.ipynb) | March 2019
-[Sharp Edges in Differentiability](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/Swift_autodiff_sharp_edges.ipynb) | September 2020
+[Sharp Edges in Differentiability](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/Swift_autodiff_sharp_edges.ipynb) | November 2020
 [Model Training Walkthrough](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/model_training_walkthrough.ipynb) | March 2019
 [Raw TensorFlow Operators](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/raw_tensorflow_operators.ipynb) | December 2019
 [Introducing X10, an XLA-Based Backend](https://colab.research.google.com/github/tensorflow/swift/blob/master/docs/site/tutorials/introducing_x10.ipynb) | May 2020