function setBackend(backendName) {
	  return ENGINE.setBackend(backendName);
	}
Sets the backend (cpu, webgl, wasm, etc) responsible for creating tensors and
executing operations on those tensors. Returns a promise that resolves
to a boolean if the backend initialization was successful.

Note this disposes the current backend, if any, as well as any tensors
associated with it. A new backend is initialized, even if it is of the
same type as the previous one.

@param backendName The name of the backend. Currently supports
    `'webgl'|'cpu'` in the browser, `'tensorflow'` under node.js
    (requires tfjs-node), and `'wasm'` (requires tfjs-backend-wasm).

@doc {heading: 'Backends'}