Coverity 1516624: Fix overrun memory access.

Not possible to hit but good to address.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #19576)

(cherry picked from commit ce0a7ca)

test/punycode_test.c

@@ -154,7 +154,7 @@ static int test_punycode(int n)
     if (!TEST_true(ossl_punycode_decode(tc->encoded, strlen(tc->encoded),
                                         buffer, &bsize)))
         return 0;
-    for (i = 0; i < sizeof(tc->raw); i++)
+    for (i = 0; i < OSSL_NELEM(tc->raw); i++)
         if (tc->raw[i] == 0)
             break;
     if (!TEST_mem_eq(buffer, bsize * sizeof(*buffer),