title: Docker task fails when Headless Chrome finishes executing Karma unit tests
body: <p>My setup is as follows:
  Angular 7, Docker, Karma, Jasmine, Headless Chrome from Puppeteer. I have 2 test suites, each with about a 100 of them, ran in parallel. Locally everything works fine, however when ran within Docker the whole build process fails the moment first suite of tests is complete.</p>
  
  <p>14-Jan-2019 11:46:02    [INFO] HeadlessChrome 72.0.3617 (Linux 0.0.0): Executed 12 of 12 SUCCESS (2.03 secs / 1.828 secs)</p>
  
  <p>is the last line of available logs I see, sometimes it even gets cut by a few letters, depending on the build.</p>
  
  <pre><code>const config = {
  basePath: '',
  frameworks: ['parallel', 'jasmine', '@angular-devkit/build-angular'],
  browserNoActivityTimeout: 50000,
  browserDisconnectTolerance: 2,
  plugins: [
      require('karma-parallel'),
      require('karma-jasmine'),
      require('karma-chrome-launcher'),
      require('karma-jasmine-html-reporter'),
      require('karma-coverage-istanbul-reporter'),
      require('@angular-devkit/build-angular/plugins/karma')
  ],
  browsers: ['customChromeHeadless'],
  port: 9241,
  singleRun: true,
  autoWatch: false,
  parallelOptions: {
      executors: 2,
      shardStrategy: 'round-robin'
  },
  reporters: ['kjhtml'],
  coverageIstanbulReporter: {
      dir: join(__dirname, '../../coverage'),
      reports: ['html', 'lcovonly', 'text-summary'],
      fixWebpackSourcePaths: true
  },
  customLaunchers: {
      customChromeHeadless: {
          base: 'ChromeHeadless',
          flags: [
              '--no-sandbox',
              '--disable-gpu',
              '--remote-debugging-port=9222'
          ]
      }
  },
  proxies: {}
  </code></pre>
  
  <p>};</p>