test/recipes/90-test_memfail.t: disable mfail before doing count runs

test/recipes/90-test_memfail.t: disable mfail before doing count runs

mfail allocator hooks installation affect memory allocation counts,
so it should be disabled for both "count" and "run" test calls.

Fixes: 3cff7c218179 "Add memory allocation failure testing framework"
Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.foundation>
Reviewed-by: Nikola Pajkovsky <nikolap@openssl.org>
MergeDate: Thu Apr 30 06:59:06 2026
(Merged from https://github.com/openssl/openssl/pull/30991)