ci: remove travis ci setup (#27937)

we no longer need it... yay!!!

PR Close #27937

tools/travis/travis-fold.js

@@ -1,21 +0,0 @@
-/**
- * @license
- * Copyright Google Inc. All Rights Reserved.
- *
- * Use of this source code is governed by an MIT-style license that can be
- * found in the LICENSE file at https://angular.io/license
- */
-
-// tslint:disable:no-console
-module.exports = function travisFoldStart(name) {
-  if (process.env.TRAVIS) console.log('travis_fold:start:' + encode(name));
-
-  return function travisFoldEnd() {
-    if (process.env.TRAVIS) console.log('travis_fold:end:' + encode(name));
-  };
-};
-
-
-function encode(name) {
-  return name.replace(/\W/g, '-').replace(/-$/, '');
-}