Add namespace util for the util.ts public methods. (#1654)
Add namespace util for the util.ts public methods. (#1654)

Fixes https://github.com/tensorflow/tfjs/issues/1465

DOC

tensorflow/tfjs-core,tensorflow/tfjs-core,tensorflow/tfjs,tensorflow/tfjs,tensorflow/tfjs,tensorflow/tfjs,tensorflow/tfjs-core,tensorflow/tfjs,tensorflow/tfjs,tensorflow/tfjs-core,tensorflow/tfjs-core,tensorflow/tfjs,tensorflow/tfjs,tensorflow/tfjs,tensorflow/tfjs-core