enable windows CI runner

[peakschris]

Once #334 closes, it would be good to enable a windows CI runner to ensure that windows does not regress. It would be good if the following configurations are tested:

1. bazel test //... --enable_runfiles
2. bazel test //... --noenable_runfiles

2 will require the bazel-starlib tests to be disabled to run clean.

@cgrindel could you assist with this?