Update radamsa and radamsa URL

[jspadaro]

Radamsa is very old, we should update the tar we include.

Radamsa URL is is very old.

[nickjenkins83]

https://gitlab.com/akihe/radamsa
Can confirm latest version of Radamsa 0.6 works on both mutiny stable and experimental.

[Thiefyface]

Experiment has been updated to use radamsa 0.6 as a submodule (probably the correct way to do it).

@jspadaro I'd recommend bumping up radamsa version, there's a huge decrease in the amount of duplicate test cases in general and it has a special mode for reducing even further (think it was ~%88 unique), but the seeds don't match up 1-1, so it'd require a fix/workaround for us when doing seed reproducibility). Might be worth adding a new cmdline option.

[jspadaro]

Gotcha, will do

[jspadaro]

This is done. Submodules aren't great in git, but we'll do it anyway.

Update: Actually updated to latest 0.6 tagged radamsa version. No love for submodules and don't want to keep pulling their dev branch on master for stability reasons.

[jspadaro]

Made issue #7 for special mode