Upgrade Rust to 1.52.0 (#17096)

* Upgrade Rust to 1.52.0
update nightly_version to newly pushed docker image
fix clippy lint errors
1.52 comes with grcov 0.8.0, include this version to script

* upgrade to Rust 1.52.1

* disabling Serum from downstream projects until it is upgraded to Rust 1.52.1

core/tests/rpc.rs

@@ -100,7 +100,7 @@ fn test_rpc_send_tx() {
         sleep(Duration::from_millis(500));
     }
 
-    assert_eq!(confirmed_tx, true);
+    assert!(confirmed_tx);
 
     use solana_account_decoder::UiAccountEncoding;
     use solana_client::rpc_config::RpcAccountInfoConfig;