bkpr: fixup htlc penalty test with anchors

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

Author: niftynei

tests/test_closing.py

@@ -7,7 +7,7 @@
     account_balance, first_channel_id, closing_fee, TEST_NETWORK,
     scriptpubkey_addr, calc_lease_fee,
     check_utxos_channel, check_coin_moves,
-    check_balance_snaps, mine_funding_to_announce, check_inspect_channel,
+    mine_funding_to_announce, check_inspect_channel,
     first_scid
 )
 
@@ -1311,7 +1311,7 @@ def test_penalty_htlc_tx_fulfill(node_factory, bitcoind, chainparams, anchors):
     l2.daemon.wait_for_log('{}.*: onchaind complete, forgetting peer'.format(l3.info['id']))
 
     assert account_balance(l3, channel_id) == 0
-    assert account_balance(l2, channel_id) == 0
+    # we can't check the account balance on l2 because it goes negative
 
     expected_2 = {
         'A': [('cid1', ['channel_open', 'opener'], ['channel_close'], 'B')],
@@ -1332,25 +1332,11 @@ def test_penalty_htlc_tx_fulfill(node_factory, bitcoind, chainparams, anchors):
         expected_3['B'].append(('external', ['anchor'], None, None))
         expected_2['B'].append(('wallet', ['anchor', 'ignored'], None, None))
         expected_3['B'].append(('wallet', ['anchor', 'ignored'], None, None))
+        # We RBF spend the HTLC tx, which creates a new deposit
+        expected_2['C'].append(('wallet', ['deposit'], None, None))
 
-    # FIXME: Why does this fail?
-    if not anchors:
-        tags = check_utxos_channel(l2, [channel_id], expected_2, filter_channel=channel_id)
-        check_utxos_channel(l3, [channel_id], expected_3, tags, filter_channel=channel_id)
-
-    if not chainparams['elements']:
-        # Also check snapshots
-        expected_bals_2 = [
-            {'blockheight': 101, 'accounts': [
-                {'balance_msat': '0msat', 'account_id': 'wallet'}
-            ]}
-        ] + [
-            {'blockheight': 108, 'accounts': [
-                {'balance_msat': '995073000msat', 'account_id': 'wallet'},
-                {'balance_msat': '500000000msat', 'account_id': first_channel_id(l1, l2)},
-                {'balance_msat': '499994999msat', 'account_id': channel_id}]}
-        ] * 2  # duplicated; we stop and restart l2 twice (both at block 108)
-        check_balance_snaps(l2, expected_bals_2)
+    tags = check_utxos_channel(l2, [channel_id], expected_2, filter_channel=channel_id)
+    check_utxos_channel(l3, [channel_id], expected_3, tags, filter_channel=channel_id)
 
 
 @unittest.skipIf(os.getenv('TEST_DB_PROVIDER', 'sqlite3') != 'sqlite3', "Makes use of the sqlite3 db")