Test flake where the balance for lightning-2 went negative
```
> assert account_balance(l2, channel_id) == 0
tests/test_closing.py:1314:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
tests/utils.py:183: in account_balance
m_sum -= Millisatoshi(m['debit_msat'])
contrib/pyln-client/pyln/client/lightning.py:193: in __sub__
return Millisatoshi(int(self) - int(other))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = -10000msat, v = -10000
```
Led me to look into this test. lightning-2 should go negative since we
roll back the amounts it's received by going to a prior database state.
Rather than trying to do the right thing with obviously broken node
records, instead we just stop trying to account for them correctly
(impossible).
I also noticed that the anchor tests were failing the utxo output
matchup, which we should be asserting on it. The HTLC RBF that our
anchor code creates was causing an issue by creating another wallet
deposit utxo under the HTLC output. We now optionally add this utxo
in the case that anchors are turned on.
Changelog-None: Fix test flake
fc08340d74