test: unflake cookie test on windows (#3489)

test/headful.spec.js

@@ -17,8 +17,8 @@
 const path = require('path');
 const os = require('os');
 const fs = require('fs');
-const rm = require('rimraf').sync;
 const {helper} = require('../lib/helper');
+const rmAsync = helper.promisify(require('rimraf'));
 const utils = require('./utils');
 const {waitEvent} = utils;
 const puppeteer = utils.requireRoot('index.js');
@@ -97,7 +97,8 @@ module.exports.addTests = function({testRunner, expect, defaultBrowserOptions})
       await headlessPage.goto(server.EMPTY_PAGE);
       const cookie = await headlessPage.evaluate(() => document.cookie);
       await headlessBrowser.close();
-      rm(userDataDir);
+      // This might throw. See https://github.com/GoogleChrome/puppeteer/issues/2778
+      await rmAsync(userDataDir).catch(e => {});
       expect(cookie).toBe('foo=true');
     });
     it('OOPIF: should report google.com frame', async({server}) => {