It seems like these benchmarks are either:

- Not useful enough to be enabled on all platforms, meaning that they should be removed altogether
- Useful enough to be enabled on all platforms

Given that we've caught several regressions with them on Mac, I think it'd be worthwhile to enable them on all desktop platforms.

Eventually, these benchmarks should be combined into power.desktop.

CCing nednguyen@ and rnephew@ to inform them of this plan, and erikchen@ because he's the owner of the original Mac-only benchmark.