Move catfile batch to a sub package of git module (#36232)

modules/git/pipeline/lfs_nogogit.go

@@ -47,12 +47,15 @@ func FindLFSFile(repo *git.Repository, objectID git.ObjectID) ([]*LFSResult, err
 
 	// Next feed the commits in order into cat-file --batch, followed by their trees and sub trees as necessary.
 	// so let's create a batch stdin and stdout
-	batchStdinWriter, batchReader, cancel, err := repo.CatFileBatch(repo.Ctx)
+	batch, cancel, err := repo.CatFileBatch(repo.Ctx)
 	if err != nil {
 		return nil, err
 	}
 	defer cancel()
 
+	batchStdinWriter := batch.Writer()
+	batchReader := batch.Reader()
+
 	// We'll use a scanner for the revList because it's simpler than a bufio.Reader
 	scan := bufio.NewScanner(revListReader)
 	trees := [][]byte{}