Switch from `normalization` to `rdf-canon` test suite

[BigBlueHat]

Handled in #182

[mielvds]

@BigBlueHat @anatoly-scherbakov Why is the rdf-canon work included in this project? What's the link with json-ld? Honestly don't know :)

Since this dependency was introduced, the rdf-canon work has moved from CG to WG. The spec is now an official recommendation and published at https://www.w3.org/TR/rdf-canon/. The test-suite at https://w3c.github.io/rdf-canon/tests/

[anatoly-scherbakov]

I remember there was a verbal discussion about it, but I do not recall any of the details :(