Fix crashes with uneven number of nocov instructions

[PragTob]

Fixes #846
We just assume them to go until the end. Test against a full nocov
for the file as well as a small mixture.

If this passes on CI I'll cut a new bugfix release.

cc: @DannyBen

[PragTob]

And it's failing on JRuby - yeehaawwww!

[PragTob]

And now github can't seem to reach the ubuntu packages or the IP is outdated and cached or what not so we can't get Java and run CI vs JRuby 😢

 Err:1 http://security.ubuntu.com/ubuntu bionic-updates/universe amd64 openjdk-8-jre-headless amd64 8u232-b09-0ubuntu1~18.04.1
  404  Not Found [IP: 52.168.50.79 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/universe/o/openjdk-8/openjdk-8-jre-headless_8u232-b09-0ubuntu1~18.04.1_amd64.deb  404  Not Found [IP: 52.168.50.79 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

[deivid-rodriguez]

I figure we could try running the workflow on https://github.com/docker-library/openjdk, so we don't need to install java everytime.

[PragTob]

yeah that seems like a great idea, right now I'm just "F5"ing hoping it comes back 😁

[PragTob]

Still borked :'(

[PragTob]

still broken, wow guess I really gotta go to docker land or something

[PragTob]

Pulled in master without JDK installation. Should hopefully pass CI now and subsequently be released 💃