Display a meaningfull error message when trying to capture a stack trace to a proxy.

test/mjsunit/regress/regress-crbug-599067.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax --harmony-tailcalls
-
 try {
-  load("mjsunit/es6/tail-call-megatest.js");
+  var o = {};
+  var p = new Proxy({}, o);
+  Error.captureStackTrace(p);
 } catch(e) {
-  load("test/mjsunit/es6/tail-call-megatest.js");
+  assertEquals("Cannot pass private property name to proxy trap", e.message);
 }
-
-run_tests(0);