[foozzie] Mock out stack traces

tools/foozzie/v8_mock.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.
 
 // This is intended for permanent JS behavior changes for mocking out
 // non-deterministic behavior. For temporary suppressions, please refer to
 // v8_suppressions.js.
 // This file is loaded before each correctness test cases and won't get
 // minimized.
 
@@ skipping 35 matching lines @@
   },
   get: function(target, property, receiver) {
     if (property == "now") {
       return __magic_mocked_date_now;
     }
   },
 }
 
 Date = new Proxy(Date, __magic_mock_date_handler);
 
+// Mock stack traces.
+Error.prepareStackTrace = function (error, structuredStackTrace) {
+  return "";
+}
+
 // Mock Worker.
 var __magic_index_for_mocked_worker = 0
 // TODO(machenbach): Randomize this for each test case, but keep stable during
 // comparison. Also data and random above.
 var __magic_mocked_worker_messages = [
   undefined, 0, -1, "", "foo", 42, [], {}, [0], {"x": 0}
 ]
 Worker = function(code){
   try {
     __PrettyPrint(eval(code));
   } catch(e) {
     __PrettyPrint(e);
   }
   this.getMessage = function(){
     __magic_index_for_mocked_worker = (__magic_index_for_mocked_worker + 1) % 10
     return __magic_mocked_worker_messages[__magic_index_for_mocked_worker];
   }
   this.postMessage = function(msg){
     __PrettyPrint(msg);
   }
 }