x_x509.c: Simplify X509_new_with_libctx() using x509_set0_libctx()
x_x509.c: Simplify X509_new_with_libctx() using x509_set0_libctx()

Reviewed-by: Shane Lontis <452ce16516ceed26291fe7de3f8b53540d83864e@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/11808)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl