Fix optimized `get_shuffling2`

[zilm13]

1. pull branch feature/testrunners
2. activate submodules git submodule update --recursive --remote
3. swap files in resources/eth2.0-tests/shuffling to uncompressed yml's from attached zip
4. modify org.ethereum.beacon.test.runner.ShuffleRunner to use get_shuffling2

expected: Test org.ethereum.beacon.test.ShuffleTests.test() passes.
actual: optimized version produces different output compared to original get_shuffling

shuffling.zip

[mkalinin]

Fixed in #112