Fix two date tests

New behavior seems much more reasonable - nothing should be able
to touch the $this value like that.

ext/date/tests/bug67118.phpt

@@ -23,4 +23,5 @@ class mydt extends datetime
 new mydt("Funktionsansvarig rådgivning och juridik", "UTC");
 ?>
 --EXPECTF--
-Fatal error: Call to a member function format() on null in %sbug67118.php on line %d
+Warning: DateTime::format(): The DateTime object has not been correctly initialized by its constructor in %s on line %d
+Bad date

ext/date/tests/bug67118_2.phpt

@@ -24,5 +24,12 @@ Done
 --EXPECTF--
 First try
 Second try
-NULL
-Done
+object(Foo)#1 (3) {
+  ["date"]=>
+  string(26) "2007-09-12 15:49:12.000000"
+  ["timezone_type"]=>
+  int(3)
+  ["timezone"]=>
+  string(3) "UTC"
+}
+Done