consider testing arg passed to done is an error object

[nlf]

currently as the documentation states

The test passes if done() is called once before the timeout, no exception thrown, and no arguments are passed to done()

I feel like this should be slightly more restrictive and also require that an argument passed to done() be an instance of Error.

As it is currently, if you pass a non-Error object to done, the reporter prints nothing. For example:

var lab = exports.lab = require('lab').script();

lab.test('shows garbage', function (done) {

  done('this isn\'t an error');
});

displays the following:

which is completely unhelpful. we should either print whatever was passed, or only error if the argument is an error object.

[devinivy]

Perhaps it could error if the argument is not an error object in a way that insists that an error object be passed.

[AdriVanHoudt]

To not suddenly let builds pass that use this I would like @devinivy said, error with a message to use an error and maybe also print what was passed

[geek]

@AdriVanHoudt and @devinivy sounds like a good plan to me

[geek]

Fixed by 35cf424