Fix permissions tests

This moves to getting a list of permissions from the device and using that to test rather than using hand written tests for each permission.

Using PermissionSettingsModule.addPermission() bypasses PermissionsTable.jsm checks for app type, so it doesn't make sense to test the affect of setting the permissions to 'allow' for each app type. Instead, I'm using getPermission to read the default values for each permission for each app type, but only running addPermission once for each permission.
Will do.