Upgrade tokio to 1.22.0 and replace async-std with tokio (#12646)

* Replace deprecated libp2p feature specs with correct ones

* Bump tokio to 1.21.2

* Replace async-std libp2p primitives with tokio ones

* minor: rustfmt

* Fix TestNet to run initialization in the tokio context

* Convert telemetry test from async-std to tokio

* Convert notifications tests from async-std to tokio

* Convert chain sync tests from async-std to tokio

* Ditch async-std completely

* Make executor mandatory

* Bump tokio to 1.22.0

* minor: rustfmt

* Explicitly use tokio runtime in tests

* Move more tests to explicit tokio runtime

* Explicitly set multithreaded runtime in tokio test

* minor: rustfmt

* minor: fix comment

* Replace async-std with tokio in MMR tests

substrate/client/service/src/builder.rs

@@ -876,9 +876,9 @@ where
 		role: config.role.clone(),
 		executor: {
 			let spawn_handle = Clone::clone(&spawn_handle);
-			Some(Box::new(move |fut| {
+			Box::new(move |fut| {
 				spawn_handle.spawn("libp2p-node", Some("networking"), fut);
-			}))
+			})
 		},
 		network_config: config.network.clone(),
 		chain: client.clone(),