Revert "rsa: expose pairwise consistency test API"

Revert "rsa: expose pairwise consistency test API"

This reverts commit dc5cd6f70a0e "rsa: expose pairwise consistency test API",
that has introduced ossl_rsa_key_pairwise_test() function, as the only user
has been removed in 7f7f75816f26 "import pct: remove import PCTs for most
algorithms".

Complements: 7f7f75816f26 "import pct: remove import PCTs for most algorithms"
Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28557)