Define a custom world creator and (optional) destroyer. These will be use to create and
destroy each World instance. Both functions can either return a value, or promise that resolves
to a value.
Parameters
creator: ()=>any
A function that creates and returns a custom World object
Optionaldestroyer: (world:any)=>Promisable<void>
An optional function to clean up the World object after each test case
Define a custom world creator and (optional) destroyer. These will be use to create and destroy each World instance. Both functions can either return a value, or promise that resolves to a value.