fix: add JSON filename in results

[regseb]

Fixes #3282

The commit 087cac8 added the addonMetadata parameter to the JSONParser and LocaleMessagesJSONParser constructors. But it was not added to the JSONParser constructor call.
The addonMetadata property is no longer in use, so I removed it from both constructors and the call to the LocaleMessagesJSONParser constructor.

[wagnerand]

I can't find where exactly, but after trademark checks got reverted in #3252, we decided to keep the addonMetadata around. @rpl do you recall that?

[willdurand]

I can't find where exactly, but after trademark checks got reverted in #3252, we decided to keep the addonMetadata around. @rpl do you recall that?

Yes, I think we should keep it for now.

[rpl]

@wagnerand personally I don't recall (but I haven't been involved in neither #3252 nor #3123).

Given that this is a regression, independently from how we will agree on fixing the issue, we should also add an additional test case along with the fix (clearly it wasn't covered enough by the existing test cases).

[regseb]

I rollbacked the modifications and added addonMetadata to the JSONParser constructor. And I checked the filename in the unit tests.