[keys] fixing nested JSProxy for-in enumeration

test/mjsunit/es6/proxies-for.js

Index: test/mjsunit/es6/proxies-for.js
diff --git a/test/mjsunit/es6/proxies-for.js b/test/mjsunit/es6/proxies-for.js
index 5b818453a9ce1726b7f685dc6159a393b007870b..a171227873228e2e81985c003bb30a0d81405e23 100644
--- a/test/mjsunit/es6/proxies-for.js
+++ b/test/mjsunit/es6/proxies-for.js
@@ -209,10 +209,15 @@ function keys(object) {
   assertThrowsEquals(() => {keys(proxy)}, "error");
 })();
 
-
-(function () {
-  var symbol = Symbol();
-  var p = new Proxy({}, {ownKeys() { return ["1", symbol, "2"] }});
-  assertEquals(["1","2"], Object.getOwnPropertyNames(p));
-  assertEquals([symbol], Object.getOwnPropertySymbols(p));
+(function testNestedProxy() {
+  var handler = {
+    ownKeys() {
+      return ['c'];
+    },
+    getOwnPropertyDescriptor() { return {configurable: true, enumerable: true } }
+  }
+  var proxy = new Proxy({}, handler);
+  var proxy2 = new Proxy(proxy, {});
+  assertEquals(['c'], keys(proxy));
+  assertEquals(['c'], keys(proxy2));
 })();