Fix timing side-channel in ECDSA signature computation

Fix timing side-channel in ECDSA signature computation

There is a timing signal of around 300 nanoseconds when the top word of
the inverted ECDSA nonce value is zero. This can happen with significant
probability only for some of the supported elliptic curves. In particular
the NIST P-521 curve is affected. To be able to measure this leak, the
attacker process must either be located in the same physical computer or
must have a very fast network connection with low latency.

Attacks on ECDSA nonce are also known as Minerva attack.

Fixes CVE-2024-13176

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/26429)