Fixes to get Windows tests running

* Abstract away the ping test for Windows instances. They have ICMP
  blocked by default
* Pass along kwargs in the Windows instance constructor
* Try twice to get the user data, until the TestListener is fixed
* Expand shell timeout to one minute, to be in line with what curl does

Change-Id: Iaedcc4a6012ff8a44ee9348da973ed749327942b