Switch from test-framework to tasty for unit testing

[rrnewton]

The last features I was waiting for have arrived, and there is now no reason not to switch the unit tests over to tasty which is newer and maintained.

Links:

• Test framework
• tasty

Though in both cases there are other supporting packages like test-framework-hunit.

[osa1]

This is done except for lvish-apps. (which we don't run in our test suite)