Prepared statement with more than 65535 columns doesn't return an error

When a statement is prepared using the binary protocol and it has more than 65535 columns in the resultset that it generates, the number of fields returned in the COM_STMT_PREPARE response only contain the lower 16 bits of the actual number of columns. This causes connectors to fail in ways that are not obvious to the user.

As a user, I would expect this to return an error that an internal limit has been exceeded.