Fix coverity 1503330 use after free

This is a false positive resulting from confusion over up_ref/free.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/18014)

test/acvp_test.c

diff --git a/test/acvp_test.c b/test/acvp_test.c
index bbc77d0..90a97e2 100644
--- a/test/acvp_test.c
+++ b/test/acvp_test.c
@@ -1381,6 +1381,8 @@
     res = 1;
 err:
     EVP_RAND_CTX_free(ctx);
+    /* Coverity is confused by the upref/free in EVP_RAND_CTX_new() subdue it */
+    /* coverity[pass_freed_arg] */
     EVP_RAND_CTX_free(parent);
     EVP_RAND_free(rand);
     return res;