BLOCKER: fork.t fails on Win32

In less than a week, we'll have 5.15.9, almost certainly the very last 5.15
release of perl.  Before 5.16.0, though, we've got a handful of blockers.

First up: #109718: fork.t fails on Win32 since v5.15.4-465-g676a678

https://rt.perl.org/rt3/Ticket/Display.html?id=109718

This clearly needs a bit of attention.  If you want to work on this, but need
access to Win32, be in touch.  If you *have* Win32 and want to have a whack at
this, it would be very appreciated.

-- 
rjbs

• BLOCKER: fork.t fails on Win32 by Ricardo Signes