refactor: dedup runtime initializations (#22263)

Co-authored-by: Alexey Shekhirin <github@shekhirin.com>

crates/node/builder/src/builder/mod.rs

@@ -985,8 +985,8 @@ impl<Node: FullNodeTypes<Types: NodeTypes<ChainSpec: Hardforks>>> BuilderContext
                 self.config().chain.clone(),
                 secret_key,
                 default_peers_path,
+                self.executor.clone(),
             )
-            .with_task_executor(self.executor.clone())
             .set_head(self.head);
 
         Ok(builder)

crates/node/builder/src/builder/states.rs

@@ -343,10 +343,7 @@ mod test {
             payload_builder_handle: PayloadBuilderHandle::<EthEngineTypes>::noop(),
         };
 
-        let task_executor = {
-            let runtime = tokio::runtime::Runtime::new().unwrap();
-            Runtime::with_existing_handle(runtime.handle().clone()).unwrap()
-        };
+        let task_executor = Runtime::test();
 
         let node = NodeAdapter { components, task_executor, provider: NoopProvider::default() };