Make OPENSSL_sk_push return only 0 or 1

Make OPENSSL_sk_push return only 0 or 1

Most of the callers do not actually check for
the special -1 return condition because they do not
pass NULL to it. It is also extremely improbable that
any code depends on this -1 return value in this condition
so it can be safely changed to 0 return.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/22930)