Define type for BLS suite test cases

[mkalinin]

Problem

It's tricky to build BLS test suite without knowing which routine is covered by a certain test case.

Solution

Specify routine for test case over a type field.

Example

case01_message_hash_G2_uncompressed:
- type: hash_to_G2_uncompressed
- input: {domain: '0x00', message: '0x6d657373616765'}
  output:
  - ['0x0e34a428411c115e094b51afa596b0e594fb325dfe42d481a87a1e89ab35f531aadc7b4f8eb5ce9d3973d2cfef8f20fd',
    '0x12830258cc04219871cd71eb9478eb1f1971104bcf49ac60ec6e3368e9047e10acef61b75d803849942bea06e3bc99a8']
  - ['0x162f48744b91343105f5b1830f3346da815ada6b615afc57c611b423470fb53d26c9e8a1e6288b524f75a8e69492cd31',
    '0x129b6b431d1d3dabda12739eadac269e7d85e2940f270b5486bfddf2c36109164dd20ba5369e9305ef16e470d0eafad0']
  - ['0x05825be2264001369d47bfac0fef4735d4cbbc8e6e0cd2f25b68948122b94a856473f07b9e6d16af7a7286bab41fc9d6',
    '0x0a2fba34dddfa47d0363fdf88d6d7fdb9db3d914f70275ea6923b3fceffee565dd7de1b2109293a72139bf3b82126a52']
case04_sign_messages:
- type: sign
- input: {domain: '0x00', message: '0x56657279202e2e2e2e2e2e2e2e2e2e2e2e2e2e206c6f6e67202e2e2e2e2e2e2e2e2e2e2e2e2e206d657373616765202e2e2e2e207769746820656e74726f70793a20313233343536373839302d626561636f6e2d636861696e',
    privkey: '0x81376b9868b292a46a1c486d344e427a3088657fda629b5f4a647822d329cd6a4620faa42d0ede402d794c367ec9c97f'}
  output: '0x09ad5dc89d7cc772cb58e61e26f4dc9fe8b43ad2a45feae2d15f09ec278ab9428dd3df9c0e2dcbee879b5436ae3609f00e2da1169b97434383157e7697f59412540a01f79ddd39a3d7df845aa4922de18723ebd66db3c69bea3e0a3240e6d3c0'

Relates to https://github.com/ethereum/eth2.0-tests/issues/14.

[djrtwo]

Agreed. The type is essentially embedded in the name right now which requires apriori knowledge of naming or ordering. We either need to pull different "types" into separate files or make it more explicit with the field imo