gh-108717: Speedup os.DirEntry.is_junction function (#108718)

Author: sobolevn

Modules/clinic/posixmodule.c.h

@@ -14576,15 +14576,13 @@ os_DirEntry_is_symlink_impl(DirEntry *self, PyTypeObject *defining_class)
 
 /*[clinic input]
 os.DirEntry.is_junction -> bool
-    defining_class: defining_class
-    /
 
 Return True if the entry is a junction; cached per entry.
 [clinic start generated code]*/
 
 static int
-os_DirEntry_is_junction_impl(DirEntry *self, PyTypeObject *defining_class)
-/*[clinic end generated code: output=7061a07b0ef2cd1f input=475cd36fb7d4723f]*/
+os_DirEntry_is_junction_impl(DirEntry *self)
+/*[clinic end generated code: output=97f64d5d99eeccb5 input=4fc8e701eea118a1]*/
 {
 #ifdef MS_WINDOWS
     return self->win32_lstat.st_reparse_tag == IO_REPARSE_TAG_MOUNT_POINT;