Jepsen 0.3.4

[Kyle Kingsbury]

Dearest generative testers,

I present, for your testing pleasure, Jepsen 0.3.4. This is a small bugfix &
performance release. Just a little faster, a little more correct, a little
easier to use. :-)

## Bugfixes

- control.util/await-tcp-port no longer logs a truncated error message
- tests.kafka no longer crashes when checking histories without any received
messages
- jepsen.independent's generators properly unlift the :value fields of the
operations they pass through to underlying generators

## Removals

- os.debian/install-jdk8! is gone now. The repos it relies on haven't worked in
years.

## Minor changes

- independent/checker uses a concurrent fold for breaking apart histories in
fewer passes. This roughly doubles throughput in tests with lots of independent
keys.
- independent/checker now returns results in a sorted map, which is easier to read
- generator.interpreter-test now tests matching open/close! invocations
- lazyfs version 0.2.0
- store.format logs more informative errors when serialization fails. You'll get
a path to the specific element that couldn't be serialized, as well as its
class. This makes serializing tests with new datatypes *much* less frustrating.

As usual, you'll find 0.3.4 on Clojars and GitHub.
https://github.com/jepsen-io/jepsen/releases/tag/v0.3.4

Happy testing!

--Kyle