These tests have been broken for about 2 years (since the TrackerResource
work landed and changed the output generated by `tracker-extract
--file`).

In this commit they are reworked with a focus on using JSON-LD rather
than doing any custom parsing of SPARQL. The test description files are
now JSON too rather than .ini format, which is not stricty needed but
should make the code a lot simpler

The failure messages could still be improved in many cases, help is
welcome here!