Assert that we get at least N task events, rather than exactly N. When a
task within an allocation dies, a sibling task can get an Allocation Unhealthy
event after it's also killed, even though it's not the origin of the event.
* Adds a constraint to prevent tests from landing on Windows
* Improve Terraform output for mixed windows/linux clients
* Makes some Windows client config fixes from 0.10.2 testing
