Adds check_inherents function to the BlockerBuilder API (#912)

* Adds new `check_inherents` function to the `BlockBuilder` API

* Switch to `check_inherents` in `node-consensus`

* Remove `CheckedBlock`, because it is not required anymore

* Fixes after rebase

* Fixes compilation on stable

substrate/core/test-runtime/src/lib.rs

@@ -185,7 +185,7 @@ impl_apis! {
 		}
 	}
 
-	impl BlockBuilder<Block, u32, u32> for Runtime {
+	impl BlockBuilder<Block, u32, u32, u32> for Runtime {
 		fn initialise_block(header: <Block as BlockT>::Header) {
 			system::initialise_block(header)
 		}
@@ -202,6 +202,10 @@ impl_apis! {
 			unimplemented!()
 		}
 
+		fn check_inherents(_block: Block, _data: u32) -> Result<(), runtime_api::BlockBuilderError> {
+			unimplemented!()
+		}
+
 		fn random_seed() -> <Block as BlockT>::Hash {
 			unimplemented!()
 		}