Correct the "Out of memory" EVP tests

Correct the "Out of memory" EVP tests

This affects test/recipes/30-test_evp_data/evpkdf_scrypt.txt and
test/recipes/30-test_evp_data/evppkey_kdf_scrypt.txt, where the "Out
of memory" stanza weren't up to the task, as they didn't hit the
default scrypt memory limit like they did in OpenSSL 1.1.1.

We solve this by setting the |n| value to the next power of two, and
correcting the expected result.

Fixes #16519

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16521)