Fix internal memory leaks from OPENSSL_MALLOC_FAILURES

Fix internal memory leaks from OPENSSL_MALLOC_FAILURES

There is a rarely used feature that can be enabled
with `./config enable-crypto-mdebug` when additionally
the environment variable OPENSSL_MALLOC_FAILURES is used.
It turns out to be possible that CRYPTO_zalloc may
create a leak when the memory is allocated and then
the shouldfail happens, then the memory is lost.
Likewise when OPENSSL_realloc is used with size=0,
then the memory is to be free'd but here the shouldfail
check is too early, and the failure may prevent the
memory to be freed thus creating a bogus memory leak.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21944)