Don't crash when size of stdout and stderr grows too big

[jamo]

In case stdout, stderr becomes too big, don't crash the system head: write error: No space left on device but rather limit he size of stdout and stderr to make this situation impossible.
The max size for logs, stdout and stderr is "free disk before running tests"/2 as we make a tar of these files.

One option would be to use scratch disks for these.