Resumable exceptions #2

[Stephen Weeks]

Not long ago, Stephen Weeks proclaimed...
> r32756
> I have now fixed the bug that prevented this from working.  The issue
> was that we weren't properly refcounting the contexts when we created
> the return continuation to resume with.  We were resuming to a freed
> context.  I've got a blog post about it I'll post sometime soon.
> 
> I also accidentally committed the 'stop disabling exception handlers'
> fix that I used to properly test that example.  I'm looking to fix the
> last misbehaving tests right now, but if I can't, I guess I'll revert
> that fix.
Not disabling exception handlers seemed to cause test 13 in
t/pmc/threads.t to blow up.  All other parrot tests seemed fine, but I
didn't really debug this one, so I reverted that behavior in r32761.

The context bug is fixed, but EHs are disabled when used still, so for
your example to work, you'll need to either set a filter on the EH or
repeatedly reenable it in itself.