Avoid leaking memory when realloc fails

Avoid leaking memory when realloc fails

In ossl_property_merge() we can drop the realloc because it just makes
the allocation smaller.

In quic-hq-interop.c we check the realloc result.

Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26244)