Use new new stat.S_ISDOOR() function, instead of hardcoded mask

Lib/test/subprocessdata/fd_status.py

@@ -3,6 +3,7 @@ file descriptors on stdout."""
 
 import errno
 import os
+import stat
 
 try:
     _MAXFD = os.sysconf("SC_OPEN_MAX")
@@ -19,6 +20,6 @@ if __name__ == "__main__":
                 continue
             raise
         # Ignore Solaris door files
-        if st.st_mode & 0xF000 != 0xd000:
+        if not stat.S_ISDOOR(st.st_mode):
             fds.append(fd)
     print(','.join(map(str, fds)))