Remove some remnants of TLS 1.3 downgrade carveouts.

Update-Note:
https://boringssl-review.googlesource.com/c/boringssl/+/44124 made these
functions a no-op, but we kept them around because there were still some
call sites floating around. That code has since been updated, so we can
remove this.

Change-Id: I25d411122d0e7a427eef5ebe8357401c0e5039d4
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/45984
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

include/openssl/ssl.h

@@ -4798,18 +4798,6 @@ OPENSSL_EXPORT int SSL_CTX_set_tlsext_status_arg(SSL_CTX *ctx, void *arg);
 // name and remove this one.
 OPENSSL_EXPORT uint16_t SSL_CIPHER_get_value(const SSL_CIPHER *cipher);
 
-// SSL_CTX_set_ignore_tls13_downgrade does nothing.
-OPENSSL_EXPORT void SSL_CTX_set_ignore_tls13_downgrade(SSL_CTX *ctx,
-                                                       int ignore);
-
-// SSL_set_ignore_tls13_downgrade does nothing.
-OPENSSL_EXPORT void SSL_set_ignore_tls13_downgrade(SSL *ssl, int ignore);
-
-// SSL_is_tls13_downgrade returns zero. Historically, this function returned
-// whether the TLS 1.3 downgrade signal would have been enforced if not
-// disabled. The TLS 1.3 downgrade signal is now always enforced.
-OPENSSL_EXPORT int SSL_is_tls13_downgrade(const SSL *ssl);
-
 
 // Nodejs compatibility section (hidden).
 //

ssl/ssl_lib.cc

@@ -2935,16 +2935,10 @@ void SSL_CTX_set_false_start_allowed_without_alpn(SSL_CTX *ctx, int allowed) {
   ctx->false_start_allowed_without_alpn = !!allowed;
 }
 
-int SSL_is_tls13_downgrade(const SSL *ssl) { return 0; }
-
 int SSL_used_hello_retry_request(const SSL *ssl) {
   return ssl->s3->used_hello_retry_request;
 }
 
-void SSL_CTX_set_ignore_tls13_downgrade(SSL_CTX *ctx, int ignore) {}
-
-void SSL_set_ignore_tls13_downgrade(SSL *ssl, int ignore) {}
-
 void SSL_set_shed_handshake_config(SSL *ssl, int enable) {
   if (!ssl->config) {
     return;