bsd-user: Implement shm_rename(2) system call

Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20230925182709.4834-7-kariem.taha2.7@gmail.com>