title: Karma disconnects with timeout even with 2 tests
body: <p>I want to use Karma test runner with tap test framework for my project and I get stuck for parallel running of tests when there are only 2 tests</p>
  
  <p>I cannot get karma to run when there is more than one test in the test folder. I have searched the issue on the net and see that most people see memory issue because of hundred tests, and mostly solve with changing timeout values. I tried changing all timeout and disconnect values but it didn't help. </p>
  
  <p>I have read all those StackOverflow pages and I don't think this is a memory et all, because the same problem is seen with only 2 test. Somehow people may though its a memory problem up to this day.</p>
  
  <p>And in the test, (this test runs all OK when it's only one test) only first step runs OK where I test the existence of my project -> t.ok(project, 'projectexist')
  after that step, I see DISCONNECT error whatever I make timeout value. I also tried to open 2 browsers didn't help (since my test needs partners from browsers.)</p>
  
  <pre><code>    browserDisconnectTimeout: 100000,
      browserNoActivityTimeout: 100000,
      browserDisconnectTolerance: 10,
  </code></pre>
  
  <p>Here is error message I get on the console</p>
  
  <pre><code>26 03 2018 09:59:37.240:WARN [Chrome 65.0.3325 (Windows 7.0.0)]: Disconnected (1 times), because no message in 10000 ms.
  Chrome 65.0.3325 (Windows 7.0.0) ERROR
    Disconnected, because no message in 10000 ms.
  Chrome 65.0.3325 (Windows 7.0.0): Executed 0 of 0 DISCONNECTED (10.214 secs / 0 secs)
  error Command failed with exit code 1.
  </code></pre>
  
  <p>And yet another interesting issue I see is, it fails with 2 exact same test, but if I chop one of them I see SUCCESS without running all steps in full test.
  let's say I have 2 tests</p>
  
  <p>1 full test
  2 1 step only test</p>
  
  <p>Note: Normally full test runs OK when there is only one test, also shows fail correctly if I make the code fail, but this situation above totally strange behavior when there are 2 tests in the folder</p>
  
  <p>karma config file</p>
  
  <pre><code>module.exports = function (config) {
    config.set({
      plugins: [
        require('karma-webpack'),
        require('karma-tap'),
        require('karma-chrome-launcher')
      ],
  
      browserDisconnectTimeout: 100000,
      browserNoActivityTimeout: 100000,
      browserDisconnectTolerance: 10,
      basePath: '',
      frameworks: ['tap'],
      files: ['test/**/*.js'],
  
      preprocessors: {
        'test/**/*.js': ['webpack']
      },
  
      webpack: {
        node: {
          fs: 'empty'
        }
      },
  
      webpackMiddleware: {
        noInfo: true
      },
  
      reporters: ['dots'],
      port: 9876,
      colors: true,
      logLevel: config.LOG_INFO,
      autoWatch: true,
      browsers: ['Chrome'],
      singleRun: false
    })
  }
  </code></pre>