Summary:
`!Object.prototype.hasOwnProperty.call(methods, unit))` doesn't correctly return `true` when an unsupported value is passed into `setMaxWidth` within an Automator (macOS) javascript/cocoascript environment.
This PR fixes the issue and also adds the `value` information to the returned error to help with debugging
Closes https://github.com/facebook/yoga/pull/643
Differential Revision: D6413569
Pulled By: emilsjolander
fbshipit-source-id: a42a66710a3ca578b5c25ecef8722f9c3f082b73