make runtime API and chain API subsystems blocking too (#2526)

polkadot/node/overseer/src/lib.rs

@@ -1557,7 +1557,7 @@ where
 			all_subsystems.runtime_api,
 			&metrics,
 			&mut seed,
-			TaskKind::Regular,
+			TaskKind::Blocking,
 		)?;
 
 		let availability_store_subsystem = spawn(
@@ -1587,7 +1587,7 @@ where
 			all_subsystems.chain_api,
 			&metrics,
 			&mut seed,
-			TaskKind::Regular,
+			TaskKind::Blocking,
 		)?;
 
 		let collation_generation_subsystem = spawn(