logalloc: Use asan to poison free areas
logalloc: Use asan to poison free areas

With this patch, when using asan, we poison segment memory that has
been allocated from the system but should not be accessible to user
code.

Should help with debugging user after free bugs.

Signed-off-by: Rafael Ávila de Espíndola <1975039f9046bf513b77c0c5639a0efc25f00e7f@scylladb.com>
Message-Id: <20190607140313.5988-1-1975039f9046bf513b77c0c5639a0efc25f00e7f@scylladb.com>

scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla