Fix a decoder mem leak on an error path
Fix a decoder mem leak on an error path

If an error condition occurs then the the decoder that was up-refed in
ossl_decoder_instance_new can be leaked.

Found due to the error report here:
https://github.com/openssl/openssl/pull/18355#issuecomment-1138205688

Reviewed-by: Tomas Mraz <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@openssl.org>
Reviewed-by: Shane Lontis <452ce16516ceed26291fe7de3f8b53540d83864e@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/18410)

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