Revisit state tests when merklization is revamped

[mkalinin]

Issue

There is a couple of tweaks have been made in order to complete State tests adoption:

• A few tests have been ignored

  beacon-chain-java/test/src/test/java/org/ethereum/beacon/test/StateTests.java

  Lines 22 to 25 in 5b35e5b

  	// FIXME: signed_root and hash_tree_root results do not match
  	"test_skipped_slots",
  	"test_empty_epoch_transition",
  	"test_historical_batch"));

• Block previous root assertion is commented out

  beacon-chain-java/consensus/src/main/java/org/ethereum/beacon/consensus/spec/BlockProcessing.java

  Lines 33 to 34 in 5b35e5b

  	// FIXME: signed_root should match
  	// assertTrue(block.getPreviousBlockRoot().equals(signed_root(state.getLatestBlockHeader())));

How to fix

Revisit State tests when following conditions are met:

• SSZ with merklization refactor is finished Refactor SSZ, implement incremental hash #115
• hash_tree_root tests are adopted and pass Tree Hash Test Generator ethereum/eth2.0-test-generators#34

[zilm13]

guess, it's not actual anymore. There are no such state tests. But we have some proof that our hash_tree_root and signing_root methods work well