Use deterministic randomness in ExampleGenerator. (#5068)

* Update samples for nodejs + nodejs-google-cloud-functions.

* Fix example generator to use deterministic randomness.

This avoids changing results after each generation, and makes diff reviews easier.

* Update NodeJS samples.

This is the last "randomness" update. From now on the samples should only change if either the generator, the input or parameters change.

samples/server/petstore/nodejs-google-cloud-functions/controllers/Pet.js

@@ -2,10 +2,8 @@
 
 var url = require('url');
 
-
 var Pet = require('./PetService');
 
-
 module.exports.addPet = function addPet (req, res, next) {
   Pet.addPet(req.swagger.params, res, next);
 };