Sync webidl tests to spec.

[davidlehn]

[davidlehn]

Also note IDL changes here:
w3c/json-ld-api#500

@gkellogg Do you know what changes are required due to the above? Should this lib still be using "JsonLdProcessor"? I'm not sure how the above effects things.

The very very out-of-date webidl tests are here:
https://github.com/digitalbazaar/jsonld.js/blob/master/tests/test-webidl.js
https://github.com/digitalbazaar/jsonld.js/tree/master/tests/webidl

[gkellogg]

The interface has always been JsonLdProcessor, going back to 1.0. In JSON-LD 1.0, WebIDL didn't have any Exposed attribute, so it wasn't relevant then. It is now, as a global, but not sure how that would actually impact an implementation.

But, it would be good if the WebIDL interface conformed to the new specification, for some value of "conform".