Fix TSNE invocation in Udacity word2vec assignment (#11482)
Fix TSNE invocation in Udacity word2vec assignment (#11482)

Default TSNE method recently changed to the approximate `method='barnes_hut'` which fails to converge per https://github.com/tensorflow/tensorflow/pull/11455
tensorflow/examples,tensorflow/examples,tensorflow/examples,tensorflow/examples,tensorflow/examples,tensorflow/examples,tensorflow/examples,tensorflow/examples,tensorflow/examples