Fix timer reference in node close handling

packages/node_modules/@node-red/runtime/lib/nodes/flows/Flow.js

@@ -573,7 +573,7 @@ function stopNode(node,removed) {
     const closePromise = node.close(removed);
     let closeTimer = null;
     const closeTimeout = new Promise((resolve,reject) => {
-        closePromise = setTimeout(() => {
+        closeTimer = setTimeout(() => {
             reject("Close timed out");
         }, nodeCloseTimeout);
     });