Parse large GOST ClientKeyExchange messages
Parse large GOST ClientKeyExchange messages

Large GOST ClientKeyExchange messages are sent by VipNet CSP, one of
Russian certified products implementing GOST TLS, when a server
certificate contains 512-bit keys.

This behaviour was present in 1.0.2 branch and needs to be restored.

Reviewed-by: Matt Caswell <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10376)

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