ecdh_cofactor_derive_test(): Skip the test if the curve is not supported

ecdh_cofactor_derive_test(): Skip the test if the curve is not supported

It will not be supported if the fips provider was built with no-ec2m.

Fixes #25729

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25731)

(cherry picked from commit 1f0cb850473048eef5dc597d8cd42dd7c3cf5a5f)