Migrate integration tests to the new blobby format

[newpavlov]

The tests were temporarily disabled in #206 and we forgot to re-enable them.

[tarcieri]

This seems like one of the last remaining blockers for a final release, particularly of hmac which otherwise seems ready to go

[tarcieri]

I tried to take a look at this and I'm completely at a loss. It seems to have completely different macro arguments that want a completely different directory structure for the blobby files, in addition to the blobby format change? It seems to now be looking for separate hmac.blb and simple_hmac.blb files