Correct ossl_sleep for threaded model by introducing sleep().

Correct ossl_sleep for threaded model by introducing sleep().

This fix handles situations where ossl_sleep() receives a millis value equal
or greater than 1000, which breaks platforms where this is not legal. The
change also avoids unnecessarily calling sleep(0).

Fixes: #23961
Signed-off-by: Randall S. Becker <randall.becker@nexbridge.ca>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23972)