Release stack trace data after firing Error.stack accessor.

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 4da38051f9200746250867e23f9cc4228c524178..a947bbfbe05aab380e6a78ca5b264d07f380ce63 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -766,18 +766,18 @@ function DefineOneShotAccessor(obj, name, fun) {
   // Note that the accessors consistently operate on 'obj', not 'this'.
   // Since the object may occur in someone else's prototype chain we
   // can't rely on 'this' being the same as 'obj'.
-  var hasBeenSet = false;
   var value;
+  var getter_function = fun;
   var getter = function() {
-    if (hasBeenSet) {
+    if (getter_function == null) {
       return value;
     }
-    hasBeenSet = true;
-    value = fun(obj);
+    value = getter_function(obj);
+    getter_function = null;
     return value;
   };
   var setter = function(v) {
-    hasBeenSet = true;
+    getter_function = null;
     value = v;
   };
   %DefineOrRedefineAccessorProperty(obj, name, getter, setter, DONT_ENUM);