This takes an extra 8 bytes per channel, but means we can go back and
get more information about them; this is implemented in
gossmap_chan_get_update_details() which is what listchannels will need.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This was likely missed because we don't run the tests under valgrind anymore
due to time constraints. I do run them on a semi-regular basis, which is why
I found this.
Now we create a separate set of local mods, and apply and unapply it.
This is more efficient than the previous approach, since we can do
some work up-front. It's also more graceful (and well-defined) when a
local modification overlaps an existing one.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
