Fire 'stack' getter of error objects after GC.

test/mjsunit/stack-traces.js

Index: test/mjsunit/stack-traces.js
diff --git a/test/mjsunit/stack-traces.js b/test/mjsunit/stack-traces.js
index 438eec979d1766ed831a45c594bc29b8e9beab7a..17cf2a64230a05d1b5a189e18dbdad9714e26203 100644
--- a/test/mjsunit/stack-traces.js
+++ b/test/mjsunit/stack-traces.js
@@ -288,4 +288,24 @@ testOmittedBuiltin(function(){ [thrower, 2].sort(function (a,b) {
                    }, "QuickSort");
 
 // Omitted because ADD from runtime.js is non-native builtin.
-testOmittedBuiltin(function(){ thrower + 2; }, "ADD");
+testOmittedBuiltin(function(){ thrower + 2; }, "ADD");
+
+var error = new Error();
+error.toString = function() { assertUnreachable(); };
+error.stack;
+
+error = new Error();
+error.name = { toString: function() { assertUnreachable(); }};
+error.message = { toString: function() {  assertUnreachable(); }};
+error.stack;
+
+error = new Error();
+Array.prototype.push = function(x) { assertUnreachable(); };
+Array.prototype.join = function(x) { assertUnreachable(); };
+error.stack;
+
+var fired = false;
+error = new Error({ toString: function() { fired = true; } });
+assertTrue(fired);
+error.stack;
+assertTrue(fired);