[runtime] Don't call GetArrayKeys on proxies.

test/mjsunit/array-sort.js

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 448 matching lines @@
   assertEquals(0, Number(Array.prototype.sort.call(x)));
   assertEquals(4, x[0]);
   assertEquals(5, x[1]);
   assertArrayEquals(["0", "1"], Object.getOwnPropertyNames(x));
   // The following would throw if ToObject weren't called.
   assertEquals(0, Number(Array.prototype.sort.call(0)));
 }
 TestSortToObject();
 
 function TestSortOnProxy() {
-  var p = new Proxy([2,1,3], {});
-  assertEquals([1,2,3], p.sort());
+  {
+    var p = new Proxy([2,1,3], {});
+    assertEquals([1,2,3], p.sort());
+  }
+
+  {
+    function f() { return arguments };
+    var a = f(2,1,3);
+    a.__proto__ = new Proxy({}, {});
+    assertEquals([1,2,3], [...(Array.prototype.sort.apply(a))]);
+  }
 }
 TestSortOnProxy();