fuzz/asn1.c: Add missing check for BIO_new

fuzz/asn1.c: Add missing check for BIO_new

Since the BIO_new may fail, the 'bio' could be NULL pointer and be used.
Therefore, it should be better to check it and skip the print if fails.

Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/17690)

(cherry picked from commit d43597c718dd6e4f2b18d5cec1eb791503a18988)