itest: remove unnecessary channel close and node shutdown

Since we don't have standby nodes anymore, we don't need to close the
channels when the test finishes. Previously we would do so to make sure
the standby nodes have a clean state for the next test case, which is no
longer relevant.

itest/lnd_onchain_test.go

@@ -153,7 +153,7 @@ func testChainKitSendOutputsAnchorReserve(ht *lntest.HarnessTest) {
 	// Charlie opens an anchor channel and keeps twice the amount of the
 	// anchor reserve in her wallet.
 	chanAmt := fundingAmount - 2*btcutil.Amount(reserve.RequiredReserve)
-	outpoint := ht.OpenChannel(charlie, bob, lntest.OpenChannelParams{
+	ht.OpenChannel(charlie, bob, lntest.OpenChannelParams{
 		Amt:            chanAmt,
 		CommitmentType: lnrpc.CommitmentType_ANCHORS,
 		SatPerVByte:    1,
@@ -207,11 +207,7 @@ func testChainKitSendOutputsAnchorReserve(ht *lntest.HarnessTest) {
 
 	// This second transaction should be published correctly.
 	charlie.RPC.SendOutputs(req)
-
 	ht.MineBlocksAndAssertNumTxes(1, 1)
-
-	// Clean up our test setup.
-	ht.CloseChannel(charlie, outpoint)
 }
 
 // testAnchorReservedValue tests that we won't allow sending transactions when