itest: enable anchor commitment for multi-hop test

These tests exercise the different ways of sweeping a commitment, so
we'll cover the modified scripts used for anchor commitments.

The only change we need for the tests to pass is to not assert exactly
which output is being swept, since this index depends on whether the
anchors are there or not.

lntest/itest/lnd_multi-hop_htlc_local_chain_claim_test.go

@@ -71,6 +71,7 @@ func testMultiHopHtlcClaims(net *lntest.NetworkHarness, t *harnessTest) {
 	allTypes := []commitType{
 		commitTypeLegacy,
 		commitTypeTweakless,
+		commitTypeAnchors,
 	}
 
 	for _, commitType := range allTypes {

lntest/itest/lnd_multi-hop_htlc_local_timeout_test.go

@@ -151,12 +151,21 @@ func testMultiHopHtlcLocalTimeout(net *lntest.NetworkHarness, t *harnessTest,
 	// We'll mine the remaining blocks in order to generate the sweep
 	// transaction of Bob's commitment output.
 	mineBlocks(t, net, defaultCSV, 1)
-	assertSpendingTxInMempool(
-		t, net.Miner.Node, minerMempoolTimeout, wire.OutPoint{
-			Hash:  *closeTxid,
-			Index: 1,
-		},
-	)
+
+	// Check that the sweep spends from the mined commitment.
+	sweepHash, err := waitForTxInMempool(net.Miner.Node, minerMempoolTimeout)
+	if err != nil {
+		t.Fatalf("unable to find bob's sweep tx: %v", err)
+	}
+	sweepTx, err := net.Miner.Node.GetRawTransaction(sweepHash)
+	if err != nil {
+		t.Fatalf("unable to get txn: %v", err)
+	}
+	// Since we cannot know for sure which index is swept, check only txid.
+	if sweepTx.MsgTx().TxIn[0].PreviousOutPoint.Hash != *closeTxid {
+		t.Fatalf("sweep transaction not spending close tx: %v",
+			spew.Sdump(sweepTx))
+	}
 
 	// Bob's pending channel report should show that he has a commitment
 	// output awaiting sweeping, and also that there's an outgoing HTLC