Implement NoProof for json tests and update tests reference (replaces #9744) (#9814)

* Update test reference.
Block test are really not working so I disabled a few by commenting
directly in source.

* Move ethtest commit cursor.

* Implements 'NoProof' engine from https://github.com/ethereum/tests/issues/464 .

Since tests has been regenerated those one were failing on block
difficulty check.

Update ethereum/tests, waiting for cost fix (block test are still
commented).

* Update tests submodule reference to latest (all test passing except an
identified case).
Fix block reward of constantinople json.

* Restore broken test by using old json tests files.

* Use CanonNoSeal instead of a custom engine, still have to include some
additional tests code.

* Gas upper limit check in json_chain test was bad, moving the test to
verification, the test is running in `verify_header_param`.
Note that test was previously only for ethash, and now for any engine.

* Restore old behavior (gas uper limit only for ethash engine), at the
cost of an additional trait method.

* Proper rpc test fix.

* Update tests submodule, add SStore bug tests.

* Fix json issue tabulation.
Update tests submodule to latest master (lot of new sstore tests
passing)

* Switch ethereum/tests to tag 6.0.0-beta.1 (no tests changes from latest
synch).

* Display hex with separator, use indirection instead of clone for copy
types.

json/src/blockchain/blockchain.rs

@@ -23,6 +23,21 @@ use blockchain::header::Header;
 use blockchain::block::Block;
 use spec::{ForkSpec, Genesis, Seal, Ethereum};
 
+/// Json Block test possible engine kind.
+#[derive(Debug, PartialEq, Deserialize)]
+pub enum Engine {
+	/// Default (old) behaviour.
+	Ethash,
+	/// No check of block's difficulty and nonce for tests.
+	NoProof,
+}
+
+impl Default for Engine {
+	fn default() -> Self {
+		Engine::Ethash
+	}
+}
+
 /// Blockchain deserialization.
 #[derive(Debug, PartialEq, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -45,6 +60,10 @@ pub struct BlockChain {
 	pub best_block: H256,
 	/// Network.
 	pub network: ForkSpec,
+	#[serde(default)]
+	#[serde(rename="sealEngine")]
+	/// Engine
+	pub engine: Engine,
 }
 
 impl BlockChain {

json/src/blockchain/mod.rs

@@ -27,6 +27,7 @@ pub mod test;
 pub use self::account::Account;
 pub use self::block::Block;
 pub use self::blockchain::BlockChain;
+pub use self::blockchain::Engine;
 pub use self::header::Header;
 pub use self::state::State;
 pub use self::test::Test;