Fix IntlGregorianCalendar double-free of an adopted TimeZone

GregorianCalendar(TimeZone*, ...) adopts the zone in the constructor.
On U_FAILURE the calendar destructor already deletes that zone, so the
extra delete tz is a double free. 8.5 and master carry the same delete,
ahead of the unique_ptr destroying the calendar rather than after it.

Author: iliaal

NEWS

@@ -10,6 +10,10 @@ PHP                                                                        NEWS
   . Fixed a use-after-free when cloning a DOMNameSpaceNode after
     DOMDocument::xinclude(). (iliaal)
 
+- Intl:
+  . Fixed a double-free when IntlGregorianCalendar construction fails after
+    the ICU constructor adopts the TimeZone. (iliaal)
+
 - Opcache:
   . Fixed opcache.protect_memory race under ZTS. (realFlowControl)
 

ext/intl/calendar/gregoriancalendar_methods.cpp

@@ -168,7 +168,6 @@ static void _php_intlgregcal_constructor_body(
 			if (gcal) {
 				delete gcal;
 			}
-			delete tz;
 			if (!is_constructor) {
 				zval_ptr_dtor(return_value);
 				RETVAL_NULL();