Remove SSL_get_structure_sizes.

With all those structures made opaque, it's not really useful as a build
sanity-check anymore.

Update-Note: This function is removed, but I don't see any actual uses.
Change-Id: Ib5640e778466da980596e7085d97104d22aa9d33
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35184
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>

include/openssl/ssl.h

@@ -3440,13 +3440,6 @@ OPENSSL_EXPORT uint64_t SSL_get_write_sequence(const SSL *ssl);
 
 // Obscure functions.
 
-// SSL_get_structure_sizes returns the sizes of the SSL, SSL_CTX and
-// SSL_SESSION structures so that a test can ensure that outside code agrees on
-// these values.
-OPENSSL_EXPORT void SSL_get_structure_sizes(size_t *ssl_size,
-                                            size_t *ssl_ctx_size,
-                                            size_t *ssl_session_size);
-
 // SSL_CTX_set_msg_callback installs |cb| as the message callback for |ctx|.
 // This callback will be called when sending or receiving low-level record
 // headers, complete handshake messages, ChangeCipherSpec, and alerts.

ssl/ssl_lib.cc

@@ -2672,13 +2672,6 @@ int SSL_cutthrough_complete(const SSL *ssl) {
   return SSL_in_false_start(ssl);
 }
 
-void SSL_get_structure_sizes(size_t *ssl_size, size_t *ssl_ctx_size,
-                             size_t *ssl_session_size) {
-  *ssl_size = sizeof(SSL);
-  *ssl_ctx_size = sizeof(SSL_CTX);
-  *ssl_session_size = sizeof(SSL_SESSION);
-}
-
 int SSL_is_server(const SSL *ssl) { return ssl->server; }
 
 int SSL_is_dtls(const SSL *ssl) { return ssl->method->is_dtls; }