ossl_rsa_check_private_exponent
int ossl_rsa_check_private_exponent(const RSA *rsa, int nbits, BN_CTX *ctx);
&& ossl_rsa_check_private_exponent(rsa, nbits, ctx)
ret = TEST_false(ossl_rsa_check_private_exponent(key, 8, ctx))
&& TEST_true(ossl_rsa_check_private_exponent(key, 8, ctx))
&& TEST_false(ossl_rsa_check_private_exponent(key, 16, ctx))
&& TEST_false(ossl_rsa_check_private_exponent(key, 8, ctx))
&& TEST_false(ossl_rsa_check_private_exponent(key, 8, ctx));