Add err check per review comments

Author: ColtonWilley

test/test_cipher.c

@@ -603,10 +603,14 @@ int test_aes_ctr_leftover_data_regression(ENGINE *e, void *data)
      * The EVP_CIPHER_CTX remembers any engine it was loaded with, meaning we
      * need to reset the ctxs before reuse or the decCtx will still pick up
      * wolfEngine */
-    if (encCtx != NULL)
-        EVP_CIPHER_CTX_free(encCtx);
-    if (decCtx != NULL)
-        EVP_CIPHER_CTX_free(decCtx);
+    if (err == 0) {
+        if (encCtx != NULL)
+            EVP_CIPHER_CTX_free(encCtx);
+    }
+    if (err == 0) {
+        if (decCtx != NULL)
+            EVP_CIPHER_CTX_free(decCtx);
+    }
 
     if (err == 0) {
         err = (encCtx = EVP_CIPHER_CTX_new()) == NULL;