Fix ReflectionClass::getConstants() stub

If `zval_update_constant_ex()` fails, an exception has already been
thrown, so we clarify that in the implementation as well.

Closes GH-6557.

Author: cmb69

ext/reflection/php_reflection.c

@@ -4446,8 +4446,7 @@ ZEND_METHOD(ReflectionClass, getConstants)
 	array_init(return_value);
 	ZEND_HASH_FOREACH_STR_KEY_PTR(&ce->constants_table, key, constant) {
 		if (UNEXPECTED(zval_update_constant_ex(&constant->value, ce) != SUCCESS)) {
-			zend_array_destroy(Z_ARRVAL_P(return_value));
-			RETURN_NULL();
+			RETURN_THROWS();
 		}
 
 		if (Z_ACCESS_FLAGS(constant->value) & filter) {

ext/reflection/php_reflection.stub.php

@@ -259,7 +259,7 @@ public function getProperties(?int $filter = null) {}
     /** @return bool */
     public function hasConstant(string $name) {}
 
-    /** @return array|null */
+    /** @return array */
     public function getConstants(?int $filter = null) {}
 
     /** @return ReflectionClassConstant[] */

ext/reflection/php_reflection_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: ec7607b8087ddd4297bf51cc4072465d2a0f27af */
+ * Stub hash: 6849bff1f2b343df4bd7e6da9c8adc555731e2d3 */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_Reflection_getModifierNames, 0, 0, 1)
 	ZEND_ARG_TYPE_INFO(0, modifiers, IS_LONG, 0)