Skip all release automation related tests on platforms which are not Linux
|Reported by:||exarkun||Owned by:|
branch-diff, diff-cov, branch-cov, buildbot
Since the release is done on Linux, and these release tools are explicitly for our use only, it's a bit of a waste to run the tests for them on other platforms, and an even bigger waste to spend development effort making the code portable and so on.
So, let's skip the tests everywhere but on Linux.