TLS requires we explicitly marshal connected sockets when using them on a different thread

Former-commit-id: 341a8caef959883ca6fc71f81f8a3fed747b2341

src/cluster.cpp

@@ -5272,6 +5272,7 @@ try_again:
         zfree(ov); zfree(kv);
         return; /* error sent to the client by migrateGetSocket() */
     }
+    connMarshalThread(cs->conn);
 
     rioInitWithBuffer(&cmd,sdsempty());
 

src/tls.cpp

@@ -349,6 +349,7 @@ connection *connCreateTLS(void) {
 
 void connTLSMarshalThread(connection *c) {
     tls_connection *conn = (tls_connection*)c;
+    serverAssert(conn->pending_list_node == nullptr);
     conn->el = serverTL->el;
 }