Fixes a bug introduced in 0aa58b9 where we're writing a test file to
a taskdir-interpolated location, which works when we `alloc exec` but
not in the jobspec for a group script check.
This changeset also makes the test safe to run multiple times by
namespacing the file with the alloc ID, which has the added bonus of
exercising our alloc interpolation code for group script checks.
Group service checks cannot interpolate task fields, because the task
fields are not available at the time the script check hook is created
for the group service. When f31482a was merged this e2e test began
failing because we are now correctly matching the script check ID to
the service ID, which revealed this jobspec was invalid.
* 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
