Fix observable array access when formatting stack trace.

src/js/messages.js

 // Copyright 2012 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.
 
 // -------------------------------------------------------------------
 
 (function(global, utils) {
 
 %CheckIsBootstrapping();
 
@@ skipping 512 matching lines @@
     try {
       return "<error: " + e + ">";
     } catch (ee) {
       return "<error>";
     }
   }
 }
 
 
 function GetStackFrames(raw_stack) {
+  var internal_raw_stack = new InternalArray();
+  %MoveArrayContents(raw_stack, internal_raw_stack);
   var frames = new InternalArray();
-  var sloppy_frames = raw_stack[0];
-  for (var i = 1; i < raw_stack.length; i += 4) {
-    var recv = raw_stack[i];
-    var fun = raw_stack[i + 1];
-    var code = raw_stack[i + 2];
-    var pc = raw_stack[i + 3];
+  var sloppy_frames = internal_raw_stack[0];
+  for (var i = 1; i < internal_raw_stack.length; i += 4) {
+    var recv = internal_raw_stack[i];
+    var fun = internal_raw_stack[i + 1];
+    var code = internal_raw_stack[i + 2];
+    var pc = internal_raw_stack[i + 3];
     // For traps in wasm, the bytecode offset is passed as (-1 - offset).
     // Otherwise, lookup the position from the pc.
     var pos = IS_NUMBER(fun) && pc < 0 ? (-1 - pc) :
       %FunctionGetPositionForOffset(code, pc);
     sloppy_frames--;
     frames.push(new CallSite(recv, fun, pos, (sloppy_frames < 0)));
   }
   return frames;
 }
 
@@ skipping 206 matching lines @@
 utils.Export(function(to) {
   to.ErrorToString = ErrorToString;
   to.MakeError = MakeError;
   to.MakeRangeError = MakeRangeError;
   to.MakeSyntaxError = MakeSyntaxError;
   to.MakeTypeError = MakeTypeError;
   to.MakeURIError = MakeURIError;
 });
 
 });