Tell the FIPS provider about thread stop events

Tell the FIPS provider about thread stop events

The RAND code needs to know about threads stopping in order to cleanup
local thread data. Therefore we add a callback for libcrypto to tell
providers about such events.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9040)