Remove the Python 3.6 fast path in PDF comparison for tests
Remove the Python 3.6 fast path in PDF comparison for tests

Even if it's not officially documented, dicts are ordered in Python 3.6. We
relied on this to assert that PDF generation was reproducible, it works on some
versions of Python 3.6 but not on Travis for some reason.

Kozea/WeasyPrint,Kozea/WeasyPrint