Fix leak when property AST evaluation fails

Author: nikic

Zend/tests/type_declarations/typed_properties_021.phpt

@@ -6,10 +6,11 @@ class Foo {
 	public int $bar = BAR::BAZ;
 }
 
-$foo = new Foo();
+try {
+    $foo = new Foo();
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
 ?>
---EXPECTF--
-Fatal error: Uncaught Error: Class 'BAR' not found in %s:%d
-Stack trace:
-#0 {main}
-  thrown in %s on line %d
+--EXPECT--
+Class 'BAR' not found

Zend/zend_API.c

@@ -1228,6 +1228,7 @@ ZEND_API int zend_update_class_constants(zend_class_entry *class_type) /* {{{ */
 
 							ZVAL_COPY(&tmp, val);
 							if (UNEXPECTED(zval_update_constant_ex(&tmp, ce) != SUCCESS)) {
+								zval_ptr_dtor(&tmp);
 								return FAILURE;
 							}
 							/* property initializers must always be evaluated with strict types */;