When a unilateral close occurs, we have to watch on-chain ("live")
HTLCs. If the other side spends their HTLC output, we need to grab
the rvalue. If it times out, we need to spend it back to ourselves.
If we get an R value, we need to spend our own HTLC output back to
ourselves.
Because there are multiple HTLCs, this doesn't fit very neatly into a
state machine. We divide into "have htlcs" and "don't have htlcs",
and use a INPUT_NO_MORE_HTLCS once all htlcs are resolved to transition.
Our test harness now tracks individual HTLCs, so we refined some
inputs (in particular, it won't try to complete/timeout an HTLC before
we have any).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
