In asn1_encode_test.c, add custom DER encoding checks

We're already checking that custom DER decodes to expected values (or
fails to do so), but we didn't check if values encode back to expected
DER.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3174)
1 file changed