Adapt ctx_lifetime test to PHP7: changed exception handling

tests/ctx_lifetime.phpt

@@ -46,10 +46,7 @@ object(V8Object)#%d (0) {
 }
 string(55) "Can't access V8Object after V8Js instance is destroyed!"
 
-Warning: Uncaught exception 'V8JsException' with message 'Can't access V8Object after V8Js instance is destroyed!' in %s%etests%ectx_lifetime.php:35
+Fatal error: Uncaught V8JsException: Can't access V8Object after V8Js instance is destroyed! in %s%etests%ectx_lifetime.php:35
 Stack trace:
-#0 %s%etests%ectx_lifetime.php(35): unknown()
-#1 {main}
+#0 {main}
   thrown in %s%etests%ectx_lifetime.php on line 35
-
-Fatal error: Call to undefined method V8Object::hello() in %s%etests%ectx_lifetime.php on line 35