Currently, there is an attempt to print FD flags, but
they are not decoded into a number, so we see something like this:
/criu # cat /proc/self/fdinfo/0
flags: {%!o(bool=000false)}
Actually, fdinfo has to contain file flags.
Change-Id: Idcbb7db908067447eb9ae6f2c3cfb861f2be1a97
PiperOrigin-RevId: 206794498