Abstract txs generation for ZKInputs tests

- TxProcessor move txCompressedDataEmpty inside the if of tp.zki!=nil
- Abstract generation of transactions for ZKInput tests to avoid code
repetition
  - used at txprocessor & test/zkproof tests

test/txsets/tilsets_test.go

@@ -0,0 +1,26 @@
+package txsets
+
+import (
+	"testing"
+
+	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/hermeznetwork/hermez-node/test/til"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCompileSetsBase(t *testing.T) {
+	tc := til.NewContext(0, common.RollupConstMaxL1UserTx)
+	_, err := tc.GenerateBlocks(SetBlockchain0)
+	assert.NoError(t, err)
+	_, err = tc.GeneratePoolL2Txs(SetPool0)
+	assert.NoError(t, err)
+}
+
+func TestCompileSetsMinimumFlow(t *testing.T) {
+	// minimum flow
+	tc := til.NewContext(0, common.RollupConstMaxL1UserTx)
+	_, err := tc.GenerateBlocks(SetBlockchainMinimumFlow0)
+	assert.NoError(t, err)
+	_, err = tc.GeneratePoolL2Txs(SetPoolL2MinimumFlow0)
+	assert.NoError(t, err)
+}