Make API backwards compatible with CC (#1697)

* Rework how a runtime api calls into the runtime

Now we generate a default implementation for each api call that calls
a generated method `method_runtime_api_impl`. This newly generated
method is the one that will be implemented by the `impl_runtime_apis`
macro in the runtime for the client side.

* Support `changed_in` to change runtime api function signatures

* Update documentation

* Fixes tests

* Implement checking the api version with a predicate

* Make the implementation backwards compatible with CC

* Update wasm files after merge

* Check for wasm runtime differences by building master and current branch

* Update spec_version and wasm files

* Fixes

* Revert my changes

* Remove `patch.crates-io` from test-runtime

substrate/core/client/src/client.rs

@@ -1426,7 +1426,7 @@ pub(crate) mod tests {
 	use runtime_primitives::generic::DigestItem;
 	use test_client::{self, TestClient};
 	use consensus::BlockOrigin;
-	use test_client::client::{backend::Backend as TestBackend, runtime_api::ApiExt};
+	use test_client::client::backend::Backend as TestBackend;
 	use test_client::BlockBuilderExt;
 	use test_client::runtime::{self, Block, Transfer, RuntimeApi, TestAPI};
 
@@ -1523,17 +1523,6 @@ pub(crate) mod tests {
 		);
 	}
 
-	#[test]
-	fn runtime_api_has_test_api() {
-		let client = test_client::new();
-
-		assert!(
-			client.runtime_api().has_api::<TestAPI<Block>>(
-				&BlockId::Number(client.info().unwrap().chain.best_number),
-			).unwrap()
-		);
-	}
-
 	#[test]
 	fn authorities_call_works() {
 		let client = test_client::new();