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/network/sync/src/service/network.rs

@@ -126,7 +126,7 @@ mod tests {
 
 	// typical pattern in `Protocol` code where peer is disconnected
 	// and then reported
-	#[async_std::test]
+	#[tokio::test]
 	async fn disconnect_and_report_peer() {
 		let (provider, handle) = NetworkServiceProvider::new();
 
@@ -147,7 +147,7 @@ mod tests {
 			.once()
 			.returning(|_, _| ());
 
-		async_std::task::spawn(async move {
+		tokio::spawn(async move {
 			provider.run(Arc::new(mock_network)).await;
 		});
 

substrate/client/network/sync/src/tests.rs

@@ -35,7 +35,7 @@ use substrate_test_runtime_client::{TestClientBuilder, TestClientBuilderExt as _
 
 // verify that the fork target map is empty, then submit a new sync fork request,
 // poll `ChainSync` and verify that a new sync fork request has been registered
-#[async_std::test]
+#[tokio::test]
 async fn delegate_to_chainsync() {
 	let (_chain_sync_network_provider, chain_sync_network_handle) = NetworkServiceProvider::new();
 	let (mut chain_sync, chain_sync_service, _) = ChainSync::new(