Make touch() $atime parameter UNKNOWN

The actual default here is $time, not 0.

Author: nikic

ext/standard/basic_functions.stub.php

@@ -942,7 +942,7 @@ function lchgrp(string $filename, $group): bool {}
 function chmod(string $filename, int $mode): bool {}
 
 #if HAVE_UTIME
-function touch(string $filename, int $time = 0, int $atime = 0): bool {}
+function touch(string $filename, int $time = 0, int $atime = UNKNOWN): bool {}
 #endif
 
 function clearstatcache(bool $clear_realpath_cache = false, string $filename = ""): void {}

ext/standard/basic_functions_arginfo.h

@@ -1443,7 +1443,7 @@ ZEND_END_ARG_INFO()
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_touch, 0, 1, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO(0, filename, IS_STRING, 0)
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, time, IS_LONG, 0, "0")
-	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, atime, IS_LONG, 0, "0")
+	ZEND_ARG_TYPE_INFO(0, atime, IS_LONG, 0)
 ZEND_END_ARG_INFO()
 #endif