Revert initsync revert (#12431)

* Revert "Revert "BeaconBlocksByRange and BlobSidecarsByRange consistency (#123… (#12426)"

This reverts commit ddc1e48e05.

* fix metrics bug, add batch.next tests

---------

Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>

beacon-chain/sync/pending_blocks_queue.go

@@ -248,7 +248,7 @@ func (s *Service) sendBatchRootRequest(ctx context.Context, roots [][32]byte, ra
 	if len(bestPeers) == 0 {
 		return nil
 	}
-	roots = s.dedupRoots(roots)
+	roots = dedupRoots(roots)
 	// Randomly choose a peer to query from our best peers. If that peer cannot return
 	// all the requested blocks, we randomly select another peer.
 	pid := bestPeers[randGen.Int()%len(bestPeers)]
@@ -456,3 +456,16 @@ func slotToCacheKey(s primitives.Slot) string {
 	b := bytesutil.SlotToBytesBigEndian(s)
 	return string(b)
 }
+
+func dedupRoots(roots [][32]byte) [][32]byte {
+	newRoots := make([][32]byte, 0, len(roots))
+	rootMap := make(map[[32]byte]bool, len(roots))
+	for i, r := range roots {
+		if rootMap[r] {
+			continue
+		}
+		rootMap[r] = true
+		newRoots = append(newRoots, roots[i])
+	}
+	return newRoots
+}