I'm investigating the problem loewis, thanks for reporting. But it would
be better if someone with running FreeBSD could help me there, in case I
find the cause for this.

Also some changes were made to the original patch:

neal.norwitz did a commit where he says:
"Using a negative time causes Linux to treat it as zero, so disable that
test."
That is not what I get here, maybe a very different kernel, anyway, I
believe he could have mentioned this here.

jeffrey.yasskin said:
".. fix some flakiness in test_itimer_prof, which could detect that the
timer had reached 0 before the signal arrived announcing that fact."

followed by these changes:

signal.setitimer(self.itimer, 0.2)        (old)
signal.setitimer(self.itimer, 0.2, 0.2)   (new) -> not sure the reason
for this change

and added:
self.assertEquals(signal.getitimer(self.itimer), (0.0, 0.0)) -> this is
the same test I did for itimer_virtual, and it is a bit questionable it
is really useful at all. I don't understand how these changes matches
what he comments on his commit.