core: use BaseExecFee from InteropContext instead of Blockchain's one

The InteropContext's one contains all relevant fee changes applied in
the prevouse transactions of the current block.

pkg/consensus/consensus.go

@@ -56,6 +56,7 @@ type Ledger interface {
 	PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error
 	SubscribeForBlocks(ch chan<- *coreb.Block)
 	UnsubscribeFromBlocks(ch chan<- *coreb.Block)
+	GetBaseExecFee() int64
 	interop.Ledger
 	mempool.Feer
 }

pkg/core/interop/context.go

@@ -37,7 +37,6 @@ const (
 type Ledger interface {
 	BlockHeight() uint32
 	CurrentBlockHash() util.Uint256
-	GetBaseExecFee() int64
 	GetBlock(hash util.Uint256) (*block.Block, error)
 	GetConfig() config.ProtocolConfiguration
 	GetHeaderHash(int) util.Uint256

pkg/core/native/interop.go

@@ -42,7 +42,7 @@ func Call(ic *interop.Context) error {
 		return fmt.Errorf("missing call flags for native %d `%s` operation call: %05b vs %05b",
 			version, m.MD.Name, ic.VM.Context().GetCallFlags(), m.RequiredFlags)
 	}
-	invokeFee := m.CPUFee*ic.Chain.GetBaseExecFee() +
+	invokeFee := m.CPUFee*ic.BaseExecFee() +
 		m.StorageFee*ic.BaseStorageFee()
 	if !ic.VM.AddGas(invokeFee) {
 		return errors.New("gas limit exceeded")