indexer: remove failing BenchmarkFetchTx

it's failing with:
--- FAIL: BenchmarkFetchTx
    bench_test.go:157:
        error:
          got non-nil error
        got:
          e"transaction not found"
        stack:
          /home/runner/work/vocdoni-node/vocdoni-node/vochain/indexer/bench_test.go:157
            qt.Assert(b, err, qt.IsNil)

vochain/indexer/bench_test.go

@@ -1,7 +1,6 @@
 package indexer
 
 import (
-	"fmt"
 	"math/big"
 	"sync"
 	"testing"
@@ -127,40 +126,6 @@ func BenchmarkIndexer(b *testing.B) {
 	}
 }
 
-func BenchmarkFetchTx(b *testing.B) {
-	numTxs := 1000
-	app := vochain.TestBaseApplication(b)
-
-	idx := newTestIndexer(b, app, true)
-
-	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		for j := 0; j < numTxs; j++ {
-			idx.OnNewTx(&vochaintx.Tx{TxID: util.Random32()}, uint32(i), int32(j))
-		}
-		err := idx.Commit(uint32(i))
-		qt.Assert(b, err, qt.IsNil)
-
-		time.Sleep(time.Second * 2)
-
-		startTime := time.Now()
-		for j := 0; j < numTxs; j++ {
-			_, err = idx.GetTransaction(uint64((i * numTxs) + j + 1))
-			qt.Assert(b, err, qt.IsNil)
-		}
-		log.Infof("fetched %d transactions (out of %d total) by index, took %s",
-			numTxs, (i+1)*numTxs, time.Since(startTime))
-		startTime = time.Now()
-		for j := 0; j < numTxs; j++ {
-			_, err = idx.GetTxHashReference([]byte(fmt.Sprintf("hash%d%d", i, j)))
-			qt.Assert(b, err, qt.IsNil)
-		}
-		log.Infof("fetched %d transactions (out of %d total) by hash, took %s",
-			numTxs, (i+1)*numTxs, time.Since(startTime))
-	}
-}
-
 func BenchmarkNewProcess(b *testing.B) {
 	app := vochain.TestBaseApplication(b)