Improve 'XMLHttpRequest' exception messages.

LayoutTests/fast/js/script-tests/dfg-custom-getter-throw.js

 description(
 "Tests that DFG custom getter caching does not break the world if the getter throws an exception."
 );
 
 function foo(x) {
     return x.status;
 }
 
 function bar(doOpen) {
     var x = new XMLHttpRequest();
     if (doOpen)
         x.open("GET", "http://foo.bar.com/");
     try {
         return "Returned result: " + foo(x);
     } catch (e) {
         return "Threw exception: " + e;
     }
 }
 
 for (var i = 0; i < 200; ++i) {
-    shouldBe("bar(i >= 100)", i >= 100 ? "\"Threw exception: InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable.\"" : "\"Returned result: 0\"");
+    shouldBe("bar(i >= 100)", i >= 100 ? "\"Threw exception: InvalidStateError: Failed to read the 'status' property from 'XMLHttpRequest': the object's state must not be OPENED.\"" : "\"Returned result: 0\"");
 }