Bug#53463: YaSSL patch appears to be reverted

The problem is that the fix Bug#29784 was mistakenly
reverted when updating YaSSL to a newer version.

The solution is to re-apply the fix and this time
actually add a meaningful test case so that possible
regressions are caught.

extra/yassl/taocrypt/src/coding.cpp:
  Fixed buffer allocation to compute the proper maximum
  decoded size: (EncodedLength * 3/4) + 3
mysql-test/std_data/server8k-cert.pem:
  Update certificate.
mysql-test/std_data/server8k-key.pem:
  Update key.
mysql-test/t/ssl_8k_key-master.opt:
  Start the server using the certificate and key that
  triggers the problem.

extra/yassl/taocrypt/src/coding.cpp

@@ -185,7 +185,7 @@ void Base64Decoder::Decode()
 {
     word32 bytes = coded_.size();
     word32 plainSz = bytes - ((bytes + (pemLineSz - 1)) / pemLineSz); 
-    plainSz = (plainSz * 3 + 3) / 4;
+    plainSz = ((plainSz * 3) / 4) + 3;
     decoded_.New(plainSz);
 
     word32 i = 0;

mysql-test/t/ssl_8k_key-master.opt

+--loose-ssl-key=$MYSQL_TEST_DIR/std_data/server8k-key.pem --loose-ssl-cert=$MYSQL_TEST_DIR/std_data/server8k-cert.pem