Yaml shuffling test vectors generator

[mratsim]

This implement a proof-of-concept YAML test vector generator.

As mentioned by @chfast, it's probably best for the test cases to be generated as artifacts during CI to avoid polluting the codebase. This single test adds 11k lines for example. 6k lines (after 4853ff3).

Anyway, the main goal is to re-sparkle testing discussion. This format can be generated, now are clients able to consume it?

Cc @djrtwo, @zscole, @rauljordan, @paulhauner

Reference spec for testing: https://github.com/ethereum/eth2.0-specs/blob/f122dd79e709c27b9259b9bd06bd95f5f45303b4/specs/test-format.md

title: Shuffling Algorithm Tests
summary: Test vectors for shuffling a list based upon a seed using `shuffle`
test_suite: shuffle
fork: tchaikovsky
version: 1.0

test_cases:
- input: []
  output: []
  seed: !!binary ""
- name: boring_list
  description: List with a single element, 0
  input: [0]
  output: [0]
  seed: !!binary ""
- input: [255]
  output: [255]
  seed: !!binary ""
- input: [4, 6, 2, 6, 1, 4, 6, 2, 1, 5]
  output: [1, 6, 4, 1, 6, 6, 2, 2, 4, 5]
  seed: !!binary ""
- input: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]
  output: [4, 7, 10, 13, 3, 1, 2, 9, 12, 6, 11, 8, 5]
  seed: !!binary ""
- input: [65, 6, 2, 6, 1, 4, 6, 2, 1, 5]
  output: [6, 65, 2, 5, 4, 2, 6, 6, 1, 1]
  seed: !!binary |
    JlAYJ5H2j8g7PLiPHZI/rTS1uAvKiieOrifPN6Moso0=

[mkalinin]

A tiny thing. Let's maybe use hexadecimal binary form? It just reads much better.

[mratsim]

Yes the generator uses hexadecimal. The test format is wrong ;).

[mratsim]

Merging this as I'd like to develop a few other tests on top of that, but feel free to keep the conversion running here.