Trivial test improvements

This commit reuses a variable instead of reevaluating the expression
and updates an outdated comment in the EVP test.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/7242)

(cherry picked from commit 523fcfb4c081ec346f117fd493103ddcd521e431)

test/evp_test.c

@@ -459,7 +459,7 @@ typedef struct cipher_data_st {
     size_t plaintext_len;
     unsigned char *ciphertext;
     size_t ciphertext_len;
-    /* GCM, CCM only */
+    /* GCM, CCM and OCB only */
     unsigned char *aad;
     size_t aad_len;
     unsigned char *tag;
@@ -487,7 +487,7 @@ static int cipher_test_init(EVP_TEST *t, const char *alg)
     if (m == EVP_CIPH_GCM_MODE
             || m == EVP_CIPH_OCB_MODE
             || m == EVP_CIPH_CCM_MODE)
-        cdat->aead = EVP_CIPHER_mode(cipher);
+        cdat->aead = m;
     else if (EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)
         cdat->aead = -1;
     else