Update image to fix asan build

The asan build was failing since some time as it needs a newer phoc. This is a bit more complicated as we need packages from experimental but that can be dropped once Debian releases as we can point to sid only then.

So update this and fix the leaks spotted. Most of them are in the tests itself but there's a single one in the notification code.

There are also new leaks in GDK/GTK (I assume uncovered since glib doesn't use the slice allocator anymore) which I need to look at separately.

We use a seperate asan image with debugging symbols so the new leak suppressions can match properly.