Possible bug in addpref.m test

The first test in prefs/addpref.m writes into /tmp/.octave_prefs
If there are two (or more) processes running at the same time they overwrite this file over.
See e.g. failures in
http://buildbot.octave.org:8010/#/builders/30/builds/365/steps/7/logs/stdio
and
http://buildbot.octave.org:8010/#/builders/16/builds/850/steps/7/logs/stdio

That looks like a bug to me.

Moreover – perhaps it is a more serious problem: what if I have two or more octave processes
running in the same working directory, could they overwrite each other prefs? Thould those be saved in some random-named files (or named per PID)?