Avoid custom sort function for builder field names.
Avoid custom sort function for builder field names.

Unless there's a meaningful difference between fieldName1 and
typeDef.allFields[fieldName1].name, I'm pretty sure the default
Array.prototype.sort function will just do the right thing, here.
Removing the custom sort function does not result in any changes to the
generated builder types, at least.

benjamn/ast-types,benjamn/ast-types,benjamn/ast-types