Add test for constructing times during the dst/st conversion.

ext/date/tests/DateTime_construct-dst-overlap.phpt

@@ -0,0 +1,15 @@
+--TEST--
+DateTime::__construct() -- fall daylight/standard overlap
+--CREDITS--
+Daniel Convissor <danielc@php.net>
+--FILE--
+<?php
+
+date_default_timezone_set('America/New_York');
+// PHP defaults to Daylight Saving Time.  Ensure consistency in future.
+$d = new DateTime('2011-11-06 01:30:00');
+echo $d->format('P') . "\n";
+
+?>
+--EXPECT--
+-04:00