If setting a secure property fails, it will force a fallback to prevent performance degredation due to exceptions

lib/util.js

@@ -493,6 +493,10 @@ function getDefineSecureProp()
             }
             catch ( e )
             {
+                // let's not have this happen again, as repeatedly throwing
+                // exceptions will do nothing but slow down the system
+                exports.secureFallback( true );
+
                 // if there's an error (ehem, IE8), fall back
                 fallback( obj, prop, value );
             }