lnwallet: add redemption+spend tests for the second-level HTLC txns
lnwallet: add redemption+spend tests for the second-level HTLC txns

aakselrod/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,LightningNetwork/lnd,AndrewSamokhvalov/lnd,aakselrod/lnd,ddustin/lnd,LightningNetwork/lnd