Don't use coordinate blinding when scalar is group order

This happens in ec_key_simple_check_key and EC_GROUP_check.
Since the the group order is not a secret scalar, it is
unnecessary to use coordinate blinding.

Fixes: #8731

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8734)

(cherry picked from commit 3051bf2afab7ac8b7b9c64e68755d1addd2fb8ff)