function isLegacyFactory (object) {
  return object && typeof object.factory === 'function'
}
Test whether an object is a factory. a factory has fields:

- factory: function (type: Object, config: Object, load: function, typed: function [, math: Object])   (required)
- name: string (optional)
- path: string    A dot separated path (optional)
- math: boolean   If true (false by default), the math namespace is passed
                  as fifth argument of the factory function

@param {*} object
@returns {boolean}