This diff will make the sanitizers to output to a log file rather than
`stderr`, which has some advantages:
- This will prevent unrelated failures in functional tests, as some
assertion are checking the `stderr` output;
- This will allow for pushing the log files the the articact list;
- This will make it easier to debug the failures, as related things
are kept together.
As a disadvantage when a sanitizer throw an error it will output nothing
to the console but still fail, creating a "failure for no visible
reason" output.