Fix possible AES leaks detected with sanitizer and clang-tidy.

Author: dgarske

wolfcrypt/src/aes.c

@@ -14060,11 +14060,16 @@ static WARN_UNUSED_RESULT int AesSivCipher(
         }
     }
 
-    aes->isAllocated = 0;
-    wc_AesFree(aes);
 #ifdef WOLFSSL_SMALL_STACK
-    XFREE(aes, NULL, DYNAMIC_TYPE_AES);
+    if (aes != NULL)
 #endif
+    {
+        aes->isAllocated = 0;
+        wc_AesFree(aes);
+    #ifdef WOLFSSL_SMALL_STACK
+        XFREE(aes, NULL, DYNAMIC_TYPE_AES);
+    #endif
+    }
 
     return ret;
 }

wolfcrypt/test/test.c

@@ -15913,8 +15913,8 @@ static wc_test_ret_t aesccm_128_test(void)
     XMEMSET(p2, 0, sizeof(p2));
     XMEMSET(iv2, 0, sizeof(iv2));
 
-#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_NO_MALLOC)
     wc_AesFree(enc);
+#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_NO_MALLOC)
     enc = wc_AesNew(HEAP_HINT, devId);
     if (enc == NULL)
         ERROR_OUT(WC_TEST_RET_ENC_EC(MEMORY_E), out);