multi: use chainntnfs.NewMiner for miners in unit tests

With the chainntnfs.NewMiner now being optimized for not creating
nodes with colliding ports, we use it in all unit tests that spin up
temporary miners.

lnwallet/btcwallet/signer_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/btcsuite/btcwallet/chain"
 	"github.com/btcsuite/btcwallet/waddrmgr"
 	"github.com/lightningnetwork/lnd/blockcache"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/stretchr/testify/require"
@@ -294,8 +295,7 @@ func TestScriptImport(t *testing.T) {
 func newTestWallet(t *testing.T, netParams *chaincfg.Params,
 	seedBytes []byte) (*BtcWallet, *rpctest.Harness) {
 
-	chainBackend, miner, backendCleanup := getChainBackend(t, netParams)
-	t.Cleanup(backendCleanup)
+	chainBackend, miner := getChainBackend(t, netParams)
 
 	loaderOpt := LoaderWithLocalWalletDB(t.TempDir(), false, time.Minute)
 	config := Config{
@@ -324,16 +324,16 @@ func newTestWallet(t *testing.T, netParams *chaincfg.Params,
 
 // getChainBackend returns a simple btcd based chain backend to back the wallet.
 func getChainBackend(t *testing.T, netParams *chaincfg.Params) (chain.Interface,
-	*rpctest.Harness, func()) {
+	*rpctest.Harness) {
 
-	miningNode, err := rpctest.New(netParams, nil, nil, "")
-	require.NoError(t, err)
-	require.NoError(t, miningNode.SetUp(true, 25))
+	miningNode := chainntnfs.NewMiner(
+		t, netParams, []string{"--txindex"}, true, 25,
+	)
 
 	// Next, mine enough blocks in order for SegWit and the CSV package
 	// soft-fork to activate on RegNet.
 	numBlocks := netParams.MinerConfirmationWindow * 2
-	_, err = miningNode.Client.Generate(numBlocks)
+	_, err := miningNode.Client.Generate(numBlocks)
 	require.NoError(t, err)
 
 	rpcConfig := miningNode.RPCConfig()
@@ -343,9 +343,7 @@ func getChainBackend(t *testing.T, netParams *chaincfg.Params) (chain.Interface,
 	)
 	require.NoError(t, err)
 
-	return chainClient, miningNode, func() {
-		_ = miningNode.TearDown()
-	}
+	return chainClient, miningNode
 }
 
 // hardenedKey returns a key of a hardened derivation key path.