Add Control.Error.Util.bool

This very same function will be present in `Data.Bool.bool` in `base>=4.7.0', but for now, it's not available in `base` so I propose its addition here.

I considered adding a CPP pragma checking for the `base` version and either defining or re-exporting `Data.Bool.bool` based on that, but it seems too cumbersome for this simple purpose.