Fix memory leak in ssltest

The new Rand usage of Thread API exposed a bug in ssltest. ssltest "cheats"
and uses internal headers to directly call functions that normally you
wouldn't be able to do. This means that auto-init doesn't happen, and
therefore auto-deinit doesn't happen either, meaning that the new rand locks
don't get cleaned up properly.

Reviewed-by: Rich Salz <rsalz@openssl.org>