[CSM-352] Return tx `amount = 0` for `A -> A` case
[CSM-352] Return tx `amount = 0` for `A -> A` case

input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype