title: webdriverIO+cucumber and i can't trigger multiple parallel tests
body: <p>i'm using wdio with cucumber frameworh, i have 2 .feature files and two test cases .js, maxInetances 10 ,
  when i trigger the test and for a briev moment two blank chrome instances are opened then one of the two is closed and the test begin executing on the remaining instance,
  the two test cases contain the same code the only difference is the content of the Given When Then  in the log there is a test which succeed and the second fails without any additional detail and when i run each test on its own they work.
  any siggestion ? </p>