Upgrade blevesearch to v0.8.1 (#9177)

For #1441

https://github.com/blevesearch/bleve/commit/a91b427b59b893f112021841ba7370d285f8426f

vendor/github.com/RoaringBitmap/roaring/manyiterator.go

@@ -4,12 +4,7 @@ type manyIterable interface {
 	nextMany(hs uint32, buf []uint32) int
 }
 
-type manyIterator struct {
-	slice []uint16
-	loc   int
-}
-
-func (si *manyIterator) nextMany(hs uint32, buf []uint32) int {
+func (si *shortIterator) nextMany(hs uint32, buf []uint32) int {
 	n := 0
 	l := si.loc
 	s := si.slice