REGTESTS: ssl: use X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY for cert check

LibreSSL-3.4.2 introduced cert revocation check behaviour change, for some
checks now X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY (20) is returned.

https://github.com/libressl-portable/portable/issues/697

let us modify vtc accordingly
2 files changed